Idaho Timeline

Chronological History of Idaho

• 8,000 to 14,000 years ago - Paleo-Indian big game-hunters, with Clovis (11,500 to 12,500 B.P), Folsom (10,500 to 11,000 B.P), and Plano (8,000 to 10,500 B.P) cultures, live in what is now Idaho.
• 200 to 8,000 years ago - Archaic-Indian culture, with permanent houses (5,000 years ago) and bows and arrows and pottery (300 to 1,500 years ago) coming into use., to present.
• 200 to 260 years ago - Shoshone bands obtain horses for transportation but are decimated by smallpox spread from European sources.

18th century

• 1743 - Discovery of the Rocky Mountains somewhere in the vicinity of Yellowstone Park made by Pierre De la Verendrye, while in search of a western sea.

19th century

• 1803 - The United States purchases Louisiana Territory from France for $15 million.
• 1805 - Captains Meriwether Lewis and William Clark discover Idaho at Lemhi Pass, and cross into north Idaho over the Lolo Trail August 12.
• 1806 - Lewis and Clark spend more than six weeks with the Nez Perce Indians in the Kamiah area before returning eastward across the Lolo Trail.
• 1809 - Britain opens the first trading post in Idaho. David Thompson constructs Kullyspell House by Lake Pend Oreille. First establishment erected in the Northwest, built for the Northwest Fur Company.
• 1810 - Fort Henry, first American fur post west of Rocky Mountains, was established by the Missouri Fur Company near St. Anthony.
• 1811 - Pacific Fur Company expedition, the Astorians, explore the Snake River Valley on their way to the Columbia River. Led by Wilson Price Hunt, the westward journey discovers the Boise Valley, which becomes a portion of the future Oregon Trail in Idaho.
• 1812 - Donald Mackenzie establishes a winter fur trading post at Lewiston for the Astorians.
• 1813 - John Reid starts fur trading post on the lower Boise River, but Bannock Indians wipe it out in 1814.
• 1818 -
  • Donald Mackenzie makes first exploration of southern Idaho with his Snake River expedition of trappers.
  • U.S. & Great Britain sign Joint Occupation Treaty for Oregon Territory.
• 1819 - Donald Mackenzie holds a rendezvous with Native Americans on the Boise River. Adams-Onis treaty between Spain and the United States establishes the southern boundary of Idaho (Oregon Territory) at 42nd parallel. Mackenzie attempts to set up a post on the Boise River.
• 1820 - Mackenzie negotiates a peace treaty with the Shoshone on Little Lost River and explores most of what would become Goodale's Cutoff.
• 1821 - Hudson's Bay Company and North West Company merge.
• 1822 - William Ashley organizes the Rocky Mountain Fur Company, which institutes the practice of annual rendezvous.
• 1823 - Battle fought in Lemhi Valley between men of the Snake River country expedition and the Piegan Indians.
• 1824 -
  • Alexander Ross and Jedediah Smith led separated expeditions to explore parts of Idaho (Salmon River Country.).
  • Peter Skene Ogden begins trapping in Idaho.
  • Russia cedes Northwest Territory to United States in a treaty.
• 1827 - A fur-trading rendezvous was held at Bear Lake.
• 1829 - Rendezvous held at Pierre's Hole, now known as the Teton basin, where hundreds of mountain men and fur trappers congregated.
• 1830 -
  • Captain B.L.E. Bonneville takes a wagon train across South Pass to Green River.
  • Rendezvous with the Indians held on the Blackfoot River, where competition in fur trading became intensely keen.
• 1831 - Fur trappers of the Rocky Mountain Fur Company, led by Kit Carson, winter on the Salmon River.
• 1832 -
  • Captain B.L.E. Bonneville leads the first crossing of the Rocky Mountains in covered wagons. The company reaches the Lemhi River on September 19. Rendezvous at Pierre's Hole.
  • Battle of Pierre's Hole occurs July 18 between American fur trappers and the Grosventre Indians.
• 1834 -
  • Fort Hall, established by Americans under Captain Nathaniel Wyeth, becomes a hub for trails and roads to the western parts of the United States.
  • Fort Boise erected by Thomas McKay of the Hudson Bay Company near the mouth of the Boise River.
  • Fort Laramie established.
• 1836 -
  • Henry Harmon Spalding and Eliza Spalding, Presbyterian missionaries, established Lapwai Mission Station. Eliza was the first white woman to travel overland to the Northwest.
  • Henry and Eliza Spalding, Presbyterian missionaries, establishes a mission near Lapwai, where Henry prints the Northwest's first book, establishes Idaho's first school, develops Idaho's first irrigation system, and grows the state's first potatoes. Eliza Spalding and Narcissa Whitman are the first white women to cross the continental divide (South Pass).
• 1837 - First white child born in Idaho is Eliza Spalding born at Lapwai.
• 1839 -
  • Henry Spalding starts publishing the Bible in Lapwai on the earliest printing press in the Pacific Northwest.
  • Chief Timothy, the first native Christian leader, baptized November 17.
• 1840 - Father Pierre Jean de Smet begins missionary work in Idaho.
• 1842 - Father Point establishes the Jesuit Coeur d' Alene Mission of the Sacred Heart near Saint Maries. The Mission moves to a site near Cataldo in 1846, and is transferred in 1877 to Desmet where it stands today.
• 1843 - Oregon Trail established in Idaho, which crossed the border near Montpelier, passed by Fort Hall, then westward south of the Snake River to the ford below Salmon Falls, then to Fort Boise, crossing the Snake River into Oregon.
• 1846 -
  • Idaho becomes part of the United States. The United States acquires all land south of 49 degrees longitude by a treaty with Great Britain. This treaty settles the Oregon boundry dispute with England.
  • Sacred Heart Mission established on the Coeur d'Alene River.
• 1848 - Oregon Territory established.
• 1849 - Over 20,000 emigrants who join the gold rush come through southeastern Idaho on the California Trail. Heavy traffic continues on the trail for many years. U.S. Military post, Cantonment Loring, is established near Fort Hall.
• 1852 - French Canadians discover gold on the Pend Oreille River.
• 1853 -
  • Construction of the Cataldo Mission completed.
  • Washington Territory is created. Idaho divided between Washington and Oregon.
• 1854 - Twenty-one emigrants led by Alexander Ward massacred in Boise Valley by the Snake River Indians. This event leads to the closing of Fort Boise the next summer and Fort Hall in 1856.
• 1855 - Salmon River mission (Fort Lemhi) is established by Mormon missionaries, to be abandoned in 1858. They began the first irrigation projects.
• 1857 - Oregon's eastern boundary (Idaho's western boundary) established by Oregon constitutional convention.
• 1858 - Bannock Indians attacked the Mormons at Fort Lemhi, killing two and driving the remaining back to Utah.
• 1859 - Oregon admitted as a state, all of Idaho included in Washington Territory.
• 1860 -
  • The first permanent settlement was established on April 14 by a group of Mormons in Franklin, just north of the Utah border.
  • Gold discovered by E. D. Pierce on Orofino Creek in August, leads to the establishment of Idaho's oldest mining town, Pierce.
  • Miss Hannah Cornish starts the first school for white children in Idaho.
  • John Mullan constructs the Mullan military wagon road built just north of Coeur d'Alene. It is to connect Fort Benton to Walla Walla.
• 1861 -
  • Lewiston established as a service community for Idaho mines on May 13.
  • Salmon River mines discovered revealing the Florence diggings causes a mining stampede October 11.
• 1862 -
  • First newspaper published in Idaho is the Golden Age in Lewiston.
  • George Grimes and a party of prospectors establish the Boise Basin mines, leads to the creation of Idaho City.
  • Packer John's Cabin built between New Meadows and McCall.
  • Gold discovered near present day Warren.
• 1863 - .
  • Boise News of Idaho City issues first copy September 29.
  • The Bear River Massacre, the West's largest slaughter of Indians, is fought near present-day Preston.
  • Mining begins in the Owyhees.
  • Idaho Territory organized, capital at Lewiston. President Lincoln signed the act establishing the territory on March 4. Soda Springs founded by Colonel Conner.
  • Boise Barracks established at Moore Creek by Major P. Lugenbeel and the U.S. Cavalry.
  • The townsite of Boise laid out by merchants under the lead of Cyrus Jacobs.
  • First general election held October 31.
  • First county established: Owyhee County, December 31.
• 1864 -
  • Public school system established for the territory.
  • Territorial Legislature on December 7 passes a resolution moving the capital from Lewiston to Boise.
  • Julius Newburg Road completed in Elmore County September 7.
  • Ben Holliday establishes first stagecoach line.
  • The Idaho Statesman begins tri-weekly publication in Boise.
  • Ada, Alturas, Boise, Idaho, Kootenai, Lah-Toh, Nez Perce, Oneida and Shoshone counties created.
  • Montana became a separate territory from the Idaho territory.
• 1865 -
  • Boise becomes the capital of Idaho.
  • J.M. Taylor and Robert Anderson erect bridge across Snake River near present day Idaho Falls.
  • Boise-Rocky Bar stage begins operations, later extended to Silver City.
• 1866 -
  • Gold discovered at Leesburg in Lemhi County.
  • Telegraph service reaches Idaho.
  • Survey of public lands begun, L.F. Cartee surveyor.
  • Congress passes Federal Lode Mining Act.
  • State of Columbia proposed by the Idaho legislature in a petition to Congress, to include all the lands in western Montana, northern Idaho, and eastern Washington.
• 1866-68 - Snake Indian War.
• 1867 -
  • Gutzon Borglum, Mount Rushmore sculptor, born in Bear Lake County March 25.
  • Owyhee Miners' League in Owyhee County organizes as state's first labor union.
  • Bishop Tuttle, an Episcopal priest, arrives in Boise October 12.
  • Idaho Legislature repeals oath of allegiance to U.S., a riot commences and Federal troops are called out.
  • Lah-Toh County abolished, territory annexed to Kootenai County.
• 1868 - Wyoming became a separate territory from the Idaho territory.
• 1869 -
  • Statue of George Washington, carved from native wood by Charles Ostner, is unveiled on the capitol grounds at Boise.
  • Idaho State Law Library established.
  • Placer gold strike made at Oro Grande.
  • Union Pacific and Central Pacific railroads complete transcontinental railway at Promontory Summit, Utah on May 10, improves transportation to Idaho.
  • Chinese workers flock to Idaho mines.
  • Fort Hall Indian Reservation set aside by President Grant for Shoshonis and Bannocks of southern Idaho.
  • First telegraph office established at Franklin, linking the town with Salt Lake City, Lemhi County created.
• 1870 -
  • Idaho population: 14,999 later census figure shows 17,804 as Utah-Idaho border was not clearly established.
  • Caribou gold rush in southeastern Idaho.
• 1872 -
  • U.S. Assay office and Idaho prison completed.
  • Strike drives Chinese labor out of Owyhee mines.
• 1873 - Coeur d'Alene Indian Reservation set aside by President Grant for the Coeur d'Alene and Spokane Indians.
• 1874 -
  • First railroad in Idaho: Utah Northern, to Franklin.
  • Idaho's first daily newspaper, The Owyhee Daily Avalanche, issued at Silver City October 17. Telegraph reaches Silver City.
• 1875 -
  • Lemhi Indian Reservation set aside by President Ulysses S. Grant for Shoshonis, Bannocks, and Tukuarikas.
  • Bear Lake County created.
  • Bank failure ruins Silver City and South Mountain Mines.
• 1877 -
  • National Desert Land Act passed by Congress for reclaiming land by irrigation.
  • The United States Army tried to force the Nez Perce Indians onto the Lapwai Reservation in Idaho.
  • Nez Perce Indian War: Warriors under Chief Joseph's command went on warpath after the government opened to settlement the Wallowa Valley in Oregon. Battles fought at White Bird - June 14th through 29th. On June 17 the battle at White Bird Canyon takes place. The Nez Perce Indians crushed the troops. Battle of Clearwater fought July 11 and 12. Fighting then moved into Montana. The war ended on October 5 with the surrender of Chief Joseph and the Nez Perce in the Bear Paw Range near the Canadian border of Montana.
  •  Duck Valley Indian Reservation set aside by President Hayes for the Shoshonis and Paiutes.
• 1878 -
  • Bannock Indian War: Bannocks led by Chief Buffalo Horn, and Paiutes led by Chief Egan, went on the warpath when the United States Government opened the Camas Prairie, which had been reserved for the Indians.
  • The Bannock Indians say they rebelled due to lack of food and other problems on their reservation. During the rebellion Chief Buffalo Horn was killed. His death caused the Indians to split into several groups. They were then defeated.
  • Battles fought at South Mountain and Bennett Creek.
• 1879 -
  • The Sheepeater Indian War: Renegade Bannocks and Tukuarika Indians go on warpath. Indians hide out in the hills of central Idaho subsisting on sheep they kill during their raids. Battles fought at Big Creek and Loon Creek. Indians surrender September 1.
  • Utah Northern railroad completed within Idaho on its path from Salt Lake City to Helena, Montana.
  • Cassia and Washington counties created.
• 1880 -
  • Idaho population: 32,619. Discovery of lead-silver lodes in the Wood River area, the rush to Bellevue, Hailey and Ketchum transforms southcentral Idaho.
  • The Boise and Lewiston Independent School Districts created.
  • North Idaho Annexation political party forms to counteract the powerful "Boise Ring".
• 1881 -
  • Historical Society of Idaho Pioneers forms to collect and preserve a reliable history of the early settlement of the territory.
  • The Hailey Times begins daily publication.
  • Wells Fargo office established at Challis.
  • Custer County created.
  • Earthquake centered 20 miles east of Mount Idaho August 9.
• 1882 -
  • Northern Pacific railroad completed across the northern part of the Territory. Construction began on the New York Canal in Ada County.
  • State's first electric light is turned on at the Philadelphia Smelter near Ketchum.
• 1883 -
  • First commercial telephone service in Idaho commenced at Hailey October 1.
  • Rexburg is founded.
  • Oregon Short Line completed through southern Idaho.
• 1884 -
  • Coeur d'Alene gold rush, followed by Tiger and Polaris mines opening lead-silver operations.
  • Silver is discovered in the Coeur d'Alene mining district, which eventually becomes nation's richest.
  • The Oregon Short Line arrives in Ketchum August 19.
  • Freight and passenger service begins on Coeur d'Alene Lake.
  • Oregon Short Line reaches Weiser, connecting Idaho to the Pacific coast.
  • Wallace is founded.
• 1885 -
  • The legislature approves construction of Territorial Capitol building at an expense of $80,000.
  • Test Oath Act adopted by legislature, designed to bar Mormons from voting and holding public office.
  • Legislature locates insane asylum at Blackfoot.
  • Famous poet Ezra Pound born at Hailey October 30.
  • Bingham County created.
  • Bunker Hill and Sullivan mines begin operation.
• 1886 -
  • Utah Northern merges with Oregon Short Line and joins Union Pacific system.
  • Separate bills to annex north Idaho to Washington Territory pass each chamber of Congress, but are not reconciled.
  • Construction on the Territorial Capitol completed.
  • Nampa city platted.
• 1887 -
  • Electric light plant goes into operation at Hailey to supply power for territory's first electric lights.
  • Wardner miner's union established after wage reductions at Bunker Hill and Sullivan mines.
  • Compulsory education law passed.
  • A bill to annex north Idaho to Washington Territory passes Congress, but is not signed by President Cleveland and does not become law.
• 1888 -
  • Ricks Academy, now known as Ricks College, established in Rexburg.
  • Latah County created by U.S. Congress.
• 1889 -
  • As a conciliatory move to keep north Idaho from seceding, the Territorial legislature locates the University of Idaho at Moscow.
  • Constitutional convention composed of sixty-eight members meet at Boise July 4 and after laboring twenty-eight days, forms and adopts constitution for the state of Idaho August 6. Constitution is ratified by the people on November 5 by a vote of 12,398 to 1,773.
  • Fire in Hailey causes $750,000 worth of damage. Elmore county created.
• 1890 -
  • Idaho population: 88,548.
  • Idaho admitted to the Union as the 43rd state on July 3, signed into law by President Benjamin Harrison. George L. Shoup became the first governor.
  • Great Northern Railroad completed across the northern part of the state.
  • Congress passes Federal Forest Reserve Act.
  • First legislative and statewide elections held.
  • First session of the Idaho Legislature meets.
• 1891 -
  • Great Seal of the State of Idaho, a design drawn by Miss Emma Edwards, with the Latin motto "Esto Perpetua" adopted.
  • Idaho forest reserves created.
  • Boise's electric street railway commences operation on August 22.
  • College of Idaho opens in Caldwell October 9. Canyon and Alta counties created.
  • President Benjamin Harrison plants Water Oak on capitol grounds.
• 1892 -
  • High freight rates and low silver prices close Coeur d'Alene mines January 16.
  • The Farmers Alliance and the Knights of Labor organize the Idaho Populist Party in Boise May 26.
  • A violent strike took place between union miners, non-union men, and mine owners in the Coeur d'Alene region.
  • Martial law commenced in the Coeur d'Alenes on July 14 following the dynamiting of the Frisco Mill near Burke.
  • University of Idaho opens October 3.
  • Idaho Education Association organized.
  • Timber and Stone Act passes Congress, paving way for commercial timber industry in Idaho.
• 1893 -
  • The "Panic of '93" lead and silver prices collapsed, Coeur d'Alene mines shut down.
  • Western Federation of Miners formed.
  • Office of State Mine Inspector established.
  • Idaho State Medical Society founded September 12.
  • State Wool Growers Association started at Mountain Home September 25.
  • First state game laws enacted.
  • State Normal Schools (Colleges of Education) established at Lewiston and Albion.
  • Legislature enacts state wagon roads to connect north and south Idaho.
  • Bannock and Fremont counties created.
• 1894 -
  • Albion Normal School opens January 8. Nez Perce Indian Reservation allotted to the Indians.
  • Congress passes Carey Act, makes possible reclamation of Snake River Valley.
  • Gold discovered in the Thunder Mountain country.
• 1895 -
  • Comprehensive irrigation law, providing for uniform use of public water, enacted on March 9.
  • Lincoln and Blaine counties created.
• 1896 -
  • Lewiston Normal School dedicated June 3.
  • Idaho becomes first in the nation in production of lead.
  • Montpelier bank robbed by Butch Cassidy August 13.
  • Idaho Legislature calls on Congress to extend the right to vote to women.
  • Idaho Republicans split, Silver Republicans endorse William Jennings Bryan for President.
  • Clashes between sheep and cattle industries culminate in the murder of sheepherders allegedly by "Diamondfield" Jack Davis.
  • Cassia County created.
• 1897 -
  • President Grover Cleveland establishes Bitterroot Forest Reserve which includes much of north Idaho.
  • Legislature acts to protect bison within the state.
  • State Board of Medical Examiners established to regulate the practice of medicine.
• 1898 -
  • First Idaho regiment of military volunteers called into service for the Philippine insurrection of the Spanish-American War.
  • Fort Hall Indian Reservation allotted to the Indians in parcels of 160 acres each, with the balance to be sold for the Indians' benefit.
• 1899 -
  • Position of State Fish and Game Warden created.
  • Governor Steunenberg declares martial law and calls in federal troops to suppress riot in the Coeur d'Alene mining district following the dynamiting of the Bunker Hill and Sullivan concentrator. Federal troops eventually brake the strike.

20th century

• 1900 -
  • Idaho population: 161,772.
  • New York Canal completed.
  • Democrats, Silver Republicans and Populists arrange party fusion for 1900 election.
  • Idaho State Dairymen's Association organized.
  • Idaho Falls incorporated.
• 1901 -
  • The Free Traveling Library (now known as the Idaho State Library) established.
  • The Academy of Idaho (now Idaho State University) opens in Pocatello.
• 1902 -
  • After concluding that Diamondfield Jack Davis had been convicted by mistake, in a case growing out of the most notable incident of the Idaho sheep and cattle wars, the State Board of Pardons turned him loose.
  • National Reclamation Act passed, provides for federal aid for irrigation.
• 1903 -
  • Idaho's hunting and fishing licensing system began.
  • The Idaho Industrial Training School founded at St. Anthony as a reform school for children.
  • First Carey Act land opening at Shoshone.
  • Miller Dam on Snake River opens Twin Falls area to irrigated farming.
  • President Theodore Roosevelt plants maple tree on capitol grounds.
• 1904 -
  • City of Twin Falls platted.
  • Chief Joseph dies September 21.
  • Completion of Milner Dam brings irrigation to the south side of the Snake River.
• 1905 -
  • Construction of a new capitol building in Boise authorized at a cost of $1,000,000.
  • Insane asylum established at Orofino.
  • The first train arrives at Twin Falls August 7.
  • Sawtooth National Forest created.
  • Former Governor Frank Steunenberg assassinated December 30, by Harry Orchard, a member of the Western Federation of Miners.
  • Ira B. Perrine started the Twin Falls Land and Water Company. It diverted water from the snake river to irrigate 60,000 acres.
• 1906 -
  • Steunenberg assassin Harry Orchard implicates three leaders of the Western Federation of Miners in the plot.
  • The largest sawmill in the United States begins operation at Potlatch.
  • The U. S. Bureau of Reclamation completed the Minidoka Dam on the Snake River.
  • Pioneer Monument at capitol grounds erected.
  • "Steward Decree" adjudicates water rights along the Boise River.
• 1907 -
  • William E. Borah elected to the U.S. Senate, where he gains an international reputation during thirty-three years of service.
  • William D. Haywood is found not guilty of conspiracy and the assassination of Frank Steunenberg, at the end of an internationally celebrated trial, Harry Orchard sentenced to life in prison for the assassination.
  • Idaho State Flag adopted.
  • Idaho Historical Society founded.
  • Weiser baseball player Walter "Big Train" Johnson signs with the Washington Senators.
  • Bonner and Twin Falls County created.
• 1908 -
  • The Idaho revised code published.
  • Under President Roosevelt's forest reserve policy, one-half of the state is organized into National Forest reserves.
  • Lake Lowell completed.
  • Idaho adopts direct primary and local option over regulation of liquor.
  • Minidoka Dam completed.
  • State Parks established at Heyburn, Shoshone Falls, and Payette Lake.
  • Allotment of Coeur d'Alene Indian Reservation.
  • Provisions for rural high school districts established.
• 1910 -
  • Idaho population: 325,594.
  • Devastating forest fire consumes 1/6 of north Idaho's forests, destroying many communities.
  • State banking and highway district laws enacted.
  • Buckeye tree planted on the capitol grounds by President William Howard Taft October 9. Search and seizure law enacted for enforcing liquor laws.
  • Idaho State Sanitarium (now known as the Idaho State School and Hospital) located at Nampa.
  • Adams, Bonneville, Clearwater and Lewis counties created.
  • Revised revenue laws enacted, providing a new system of assessment, equalization, levy and collection of taxes.
  • Constitutional amendments adopted authorizing initiative, referendum, and recall.
  • State Board of Education established to supervise all levels of education within the state of Idaho.
• 1912 - State Board of Education is established.
• 1913 -
  • Public Utilities Commission established.
  • Northwest Nazarene College in Nampa founded.
  • First motor vehicle laws enacted by the legislature.
  • Comprehensive system of revenue for state, county, municipal and school purposes enacted.
  • School for the Deaf and Blind opens in Gooding.
  • Franklin, Gooding, Jefferson, Madison, Minidoka and Power counties created.
• 1914 - Moses Alexander is first elected Jewish governor in United States.
• 1915 -
  • Arrowrock Dam completed.
  • Columbia and Snake River improvements for navigation to Lewiston completed.
  • Second Idaho Regiment of Infantry Volunteers organized into service at the call of President Woodrow Wilson for the Mexican Border War.
  • The Academy of Idaho (now Idaho State University) becomes the Idaho Technical Institute.
  • Idaho Horse and Cattle Association organized, later to become the Idaho Cattlemen's Association.
  • Benewah, Boundary, Gem and Teton counties created.
• 1916 -
  • Constitutional amendment for statewide prohibition ratified.
  • State highway program begins as part of the national good roads movement.
• 1917 -
  • Statewide prohibition goes into effect January 1.
  • Workmen's Compensation System and State Insurance Fund established.
  • Annual state fair established at Boise.
  • Ricks Academy becomes a college and is accredited by the State Board of Education.
  • Butte, Camas, Payette and Valley counties created.
  • Battleship Idaho is launched.
  • After the United States entered World War I, the agriculture economy boomed in Idaho.
• 1918 -
  • Non-Partisan League takes over Idaho Democratic primary September 3, subsequently Idaho's primary nominating system is abandoned for twelve years.
  • After WWI ended the agricultural boom ended causing a huge collapse.
• 1919 -
  • Administrative consolidation enacted by legislature.
  • Functions of fifty-one departments, boards and bureaus placed under nine administrative departments responsible to the governor.
  • Bureau of Highways created to inaugurate a state highway system.
  • Bureau of Constabulary organized May 18, with Department of Law Enforcement.
  • First Music Week held in Boise.
  • Lava Hot Springs established by Department of Public Welfare.
  • City of Jerome incorporated.
  • Jerome, Clark, and Caribou counties created.
• 1920 -
  • Idaho population: 431,866.
  • Philo Farnsworth, 15-year-old student and inventor from Rigby, develops concepts that lead to invention of television and earn him the name "Father of Television." Idaho's first radio station, KFAU, at Boise High School, goes on the air in 1922.
  • Agricultural prices begin to deteriorate, creating a crisis which continues through the 1920's.
  • Whitebird Hill grade, connecting north and south Idaho opens.
  • State Capitol completed.
  • Idaho Wheat Growers Association formed.
  • Constitutional amendment increases State Supreme Court from three to five members.
• 1922 -
  • State budget system established.
  • Radio broadcasting begins in Idaho with station KFAU located at Boise High School under the direction of Harry Redeker.
• 1924 -
  • Craters of the Moon National Monument established.
  • Black Canyon Dam completed.
• 1925 -
  • Union Pacific Railroad begins service to Boise.
  • State Forestry Board established.
  • William E. Borah becomes Chairman of the Senate Committee on Foreign Relations.
• 1926 -
  • The Idaho State Chamber of Commerce organized.
  • First commercial airmail service came to the Northwest with a Pasco, Washington to Elko, Nevada flight with a stop in Boise.
• 1927 -
  • American Falls Dam completed.
  • Perrine Memorial Bridge at Twin Falls completed. Palisades Reservoir created.
  • Idaho Technical Institute in Pocatello redesignated the University of Idaho Southern Branch.
• 1928 -
  • Restoration of the "Old Mission" church near Cataldo begins.
  • Commercial radio broadcasting begins in Idaho with the purchase of KFAU from Boise High School and renamed KIDO.
• 1930 - Idaho population 445,032.
• 1931 -
  • The direct primary restored for statewide offices.
  • State income tax adopted.
  • U.S. Forest Service, in cooperation with the state Legislature, create the Idaho Primitive Area.
  • Legislature adopts "Here We Have Idaho" as state song, the syringa the official flower, and the Rocky Mountain Bluebird the state bird.
• 1932 -
  • Nonpartisan election of judges to Supreme Court and District Courts enacted.
  • The Idaho Code annotated published.
  • Six million dollar Owyhee Dam dedicated.
  • Association of Idaho Veterans of Foreign Wars organized.
  • Boise Junior College opens.
• 1933 - 
  • School Equalization Law adopted.
  • North Idaho Junior College established at Coeur d'Alene.
• 1934 -
  • Sandpoint Bridge completed.
  • Taylor Grazing Act passes U.S. Congress. Central and northern Idaho experience large mining developments for gold and silver.
  • Idaho becomes first in the nation in silver production.
• 1935 -
  • Statewide prohibition repealed and State adopts Liquor Dispensary system.
  • Indian children begin integration into public school system.
  • State employment service established.
  • Two percent sales tax enacted, but rejected by voters in referendum in 1936.
  • Legislature provides for purchase of the site of Spalding Mission as a state park.
  • Martial law declared in Teton County to put down a rebellion of pea pickers.
• 1936 -
  • Sun Valley established as a ski resort by the Union Pacific Railway in September. World's first ski chair lift opens.
  • Martial law declared in Clearwater County during I.W.W. lumber strike.
  • Celebration held in Lewiston to commemorate the 100th anniversary of the founding of Spalding Mission.
  • In March, William E. Borah became Idaho's first Presidential candidate.
• 1937 - Open primary system does away with requirement for declaration of party affiliation.
• 1938 -
  • Paving of the north-south highway (U.S. 95) completed.
  • Fish and Game Commission established by initiative.
  • Idaho Senator James P. Pope sponsors Agricultural Adjustment Act.
• 1939 -
  • State Junior College district law enacted.
  • Idaho State Police established March 13.
  • Joe Albertson opens his first supermarket in Boise.
• 1940 -
  • Idaho population: 524,873.
  • Senator William E. Borah dies January 19.
  • Legislation creating a position of Comptroller to be appointed by the Governor, and taking away many powers of the State Auditor, ruled unconstitutional by the Courts.
• 1941 -
  • Gowen Field completed south of Boise and becomes a military air base
  • J.R. Simplot begins potato dehydration operations in Caldwell.
• 1942 -
  • Farragut Naval Training Station established at Lake Pend Oreille.
  • Camp Minidoka was set up, near Eden. An internment camp for Japanese-Americans. They worked on potato and sugar beet farms.
  • A Pocatello army air base and gun relining plant established.
  • Japanese-Americans placed in internment camps at Hunt.
  • Two anti-liquor initiatives rejected by the voters.
  • Mountain Home Air Base site was approved.
• 1944 - Mountain Home Army Air Field officially opened.
• 1945 -
  • State Tax Commission established.
  • Idaho's first phosphate processing plant constructed by the J.R. Simplot Company.
• 1946 -
  • Most recent Idaho Code published.
  • A teacher's retirement system established.
  • Election of Idaho's governor and other state officials for four-year terms begin.
  • Two anti-liquor initiatives and an anti-gambling initiative defeated.
• 1947 -
  • A state school reorganization plan enacted.
  •  University of Idaho Southern Branch at Pocatello becomes Idaho State College.
  • State Board of Corrections established.
  • Idaho State Archives established.
• 1948 -
  • Bureau of Reclamation begins plans to construct a Hell's Canyon dam in the Snake River for flood control.
  • Idaho Senator Glen Taylor runs for Vice-President on Progressive Party ticket.
• 1949 - The Atomic Energy Commission built the National Reactor Testing Station near Idaho Falls.
• 1950 -
  • Idaho population: 588,637.
  • State Highway Department established with provisions for nonpolitical administration.
• 1951 -
  • In December NRTS becomes site of the worlds' first use of nuclear fission to produce electricity. Experimental Breeder Reactor No. 1 is later designated a National Landmark.
  • State teacher's colleges at Lewiston and Albion are closed.
• 1952 - Anderson Ranch Dam completed.
• 1953 -
  • Television comes to Idaho with KIDO-TV (now KTVB) in Boise July 12.
  • C.J. Strike Dam dedicated.
  • Supreme Court rules against Idaho law legalizing slot machines and other lottery devices.
• 1954 -
  • Submarine reactor tested and perfected at the National Reactor Testing Station.
  • Voters approve initiative to regulate dredge mining.
• 1955 -
  • State Department of Commerce and Development established.
  • Lewis-Clark Normal opens at Lewiston.
  • Lucky Peak Dam dedicated July 6.
  • Acro became the first community to receive its entire power supply from nuclear energy.
  • The Idaho Power Company began to build three dams on the Snake River.
• 1956 -
  • Construction of Palisades Dam completed.
  • Construction in Idaho of the National Interstate Highway System commenced.
  • Constitutional amendment ratified to permit a governor to succeed himself for reelection.
• 1958 -
  • Boise-Stanley Highway Association established.
  • Voters defeat "Right to Work" initiative.
• 1959 - The Brownlee Dam was completed.
• 1960 -
  • Idaho population: 667,191.
  • Seven month strike at Bunker Hill Mine.
  • July and August forest fires in Hells Canyon and Idaho City area.
  • State employee group insurance system established.
• 1961 -
  • Oxbow Dam completed on Snake River.
  • W.A. Harriman and E. Rolland Harriman provided that their holdings at Railroad Ranch eventually become a state park, providing that the state establish a professionally managed park system.
  • Ernest Hemingway commits suicide in Ketchum July 2.
• 1962 - Lewis and Clark highway (U.S. 12) in the Lochsa Canyon completed.
• 1963 -
  • Legislative Council established.
  • Idaho State College in Pocatello attains University status.
  • Lewis-Clark Normal becomes a four year college.
  • Horse Racing Act, to permit pari-mutuel betting, becomes law over Governor's veto (first override in twenty years).
  • Idaho celebrates Territorial Centennial.
• 1964 -
  • Combined convention and primary system implemented, parties attempt to restrict the number of state primary candidates appearing on the ballot.
  • Federal Court ends Bible reading in Boise public schools.
• 1965 -
  • State parks department, water resource board, and personnel system created.
  • Nez Perce National Historic Park established in north-central Idaho.
  • Boise Junior College given 4-year status.
• 1966 -
  • Governor Smylie defeated for 4th term.
  • Voters uphold 3% sales tax in referendum.
  • Northern Pacific ends passenger service between Lewiston and Spokane.
• 1967 -
  • Legislative Compensation Commission established.
  • International Boy Scout Jamboree held at Farragut State Park.
• 1968 - The Hell's Canyon Dam was completed.
• 1969 - Annual legislative sessions commence.
• 1970 -
  • Idaho population: 713,015.
  • Voters reject proposed revision of Idaho Constitution.
  • Voters pass strict legislative pay initiative.
  • National Farmers Organization stages 120 vehicle caravan to Boise to protest potato prices.
• 1971 -
  • Legislature enacts a stream protection law. Last log drive on the Clearwater River.
  • Rail passenger service ends May 1 for all places in Idaho except Sandpoint.
  • Fire destroys $25,000 worth of property during a riot at the Idaho State Penitentiary.
• 1972 -
  • New Idaho uniform probate code goes into effect.
  • An underground fire occurred in the Sunshine silver mine near Kellogg. 91 people were killed.
  • Idaho voters return to open primary system.
  • Sawtooth National Recreation Area established, includes the Sawtooth Wilderness Area.
  • Dworshak Dam completed.
  • Constitutional amendment adopted requiring state government reorganization into no more than 20 agencies.
• 1973 -
  • U.S. Congress passes a bill to replace the deteriorating American Falls Dam.
  • Boise State College attains university status.
• 1974 -
  • State agencies reorganized into 19 departments.
  • Kootenai Indians in northern Idaho declare war on the U.S. government to gain money and land.
  • Voters pass the Sunshine Initiative to require lobbyist registration and political campaign disclosure.
  • Evel Knievel fails in attempt to ride his "Skycycle" across the Snake River canyon near Twin Falls.
• 1975 -
  • Presidential preference primary to be held on the fourth Tuesday of May adopted.
  • White Bird Hill bypass opens June 16.
  • Legislature passes Local Planning and Zoning Act.
  • New prison opens south of Boise.
  • Port of Lewiston opens Idaho to ocean-going shipping.
• 1976 -
  • Hells Canyon bill creates the scenic Hells Canyon National Recreation Area, and bans construction of hydroelectric projects in the canyon.
  • Senator Frank Church becomes a candidate for President, the first Idahoan since William E. Borah in 1936.
  • The 310 foot high Teton Dam collapses in southeastern Idaho, killing 11 and forcing 300,000 people to flee their homes.
  • Constitutional amendment creates Citizens Committee on Legislative Compensation.
  • The Public Utilities Commission rejects proposal by Idaho Power Company to build an electric coal-fired power plant between Boise and Mountain Home.
• 1977 -
  • Governor Cecil D. Andrus resigns to become Secretary of the Interior.
  • Legislature rescinds their 1972 ratification of the Equal Rights Amendment.
  • Many Idaho counties declared disaster areas due to severe drought.
  • Boise, Nampa, Mountain Home, Shoshone, and Pocatello become stops on Amtrak's Seattle-Ogden line
• 1978 -
  • President Jimmy Carter floats the River of No Return in central Idaho.
  • Voters pass initiative limiting property taxes to 1 percent of market value.
  • Pocatello businessman Bill Barlow wins U.S. Supreme Court decision against Occupational Safety and Health Administration.
• 1979 -
  • An investigation by the Idaho Statesman reveals that plutonium had been injected into the Snake River plain aquifer at the Idaho National Engineering Laboratory.
  • Senator Frank Church becomes Chairman of the Senate Committee on Foreign Relations
• 1980 -
  • Idaho population: 944,038.
  • An 18 hour riot at the Idaho State Prison results in $2 million in damages.
  • Mount St. Helens erupts, covers north Idaho with volcanic ash.
  • Interior Secretary Cecil Andrus, by executive order, expands the Birds of Prey Natural Area from 31,000 to 482,640 acres.
  • Congress approves the Central Idaho Wilderness Act, establishing the 2.2 million acre River of No Return Wilderness.
  • Congressman Steve Symms defeats Senator Frank Church in the most expensive campaign in Idaho history with over $4 million spent by the candidates and independent committees.
• 1981 -
  • Senator James McClure becomes Chairman of the Senate Committee on Energy and Natural Resources.
  • Keith F. Nyborg, a rancher from Ashton, is appointed ambassador to Finland by President Reagan.
  • "Rabbit Drives" in southeastern Idaho create controversy between animal protection groups and farmers whose crops are devastated by wild jack rabbits.
  • Gulf Resources and Chemical of Houston, Texas announced the closure of the 98-year-old Bunker Hill Mine and Smelter in Kellogg.
• 1982 -
  • Legislature outlaws insanity plea for defendants - first in nation.
  • Voters pass record eight constitutional amendments and three initiatives.
  • Governor Evans puts most state employees on 4-day work week for two months to lower projected budget deficit.
  • Harriman State Park dedicated July 17.
  • Fugitive Christopher Boyce, convicted of selling national security secrets to the Soviet Union, is captured near Bonners Ferry.
• 1983 -
  • Eagle Island State Park dedicated June 25.
  • Legislature imposes temporary 4 1/2 percent sales tax to cover state deficit.
  • State Supreme Court declares current legislative apportionment unconstitutional because it divides counties.
  • Several north Idaho local governments pass resolutions to secede from southern Idaho and form a new state.
  • An earthquake measuring 7.3 on the Richter scale, kills two children and causes four million dollars worth of damage on October 28. The quake, centered in the Lost River Valley, was the largest in the continental United States in 24 years and left a 10-foot high, 15 mile long shear.
• 1984 -
  • Supreme Court imposes 42 member Senate, 84 member House in legislative redistricting plan.
  •  Christin Cooper of Ketchum wins silver medal in the women's giant slalom at the Olympic games in Sarajevo, Yugoslavia.
  • Harmon Killebrew of Payette is inducted into the Baseball Hall of Fame.
  • Permanent sales tax set at 4 percent.
  • Legislature approves Education Reform bill, allocating $20 million to improve teacher salaries statewide.
  • Former Senator Frank Church dies April 7.
  • U.S. Representative George Hansen defeated for reelection by Richard Stallings in closest Idaho congressional race in history - 170 votes.
  • Populist Party sues for and obtains ballot status on November 6 general election.
  • Wallace celebrates centennial.
  • Idaho Power Company and the State of Idaho reach agreement on Snake River Basin water rights.
• 1985 -
  • Shortest Legislative session in 12 years - 66 days.
  • David Marquart (Boise) and Barbara Morgan (McCall) are among 10 finalists out of 11,000 applicants in the NASA Teacher in Space program. Barbara Morgan later becomes Teacher in Space backup to Christa McAuliffe, and Teacher in Space designee in 1986, and later the first education mission specialist.
  • Department of Commerce established.
  • National Governor's Conference held in Boise.
  • Jimmy Jausoro, a Basque musician from Boise is one of 12 folk artists nationwide (and the first Idahoan ever) to receive a prestigious 1985 National Heritage Fellowship from the National Endowment for the Arts.
  • Pocatello citizens vote to remove council-manager system of city government in June.
  • Potlatch Corporation closes lumber mills at Lewiston and Jaype (near Pierce), affecting 1,200 workers.
  • Over six million acres of Idaho rangeland are sprayed with pesticides to battle grasshopper infestation.
• 1986 -
  • Claude Dallas, convicted in 1982 for killing two Idaho Fish & Game Wardens, escapes from the Idaho State Penitentiary March 30.
  • He is recaptured March 8, 1987 outside a convenience store in Riverside, California.
  • Voters retain right-to-work law in referendum; also approve state lottery initiative.
• 1987 -
  • Permanent sales tax at 5 percent.
  • Legislature passes mandatory daycare licensing and tort reform legislation.
  • Dry winter leads to severe summer drought.
• 1988 - Voters pass constitutional amendment removing prohibition against legislature authorizing a state lottery.
• 1989 -
  • First state lottery tickets sold July 19th.
  • Worst forest fires since 1910, burn thousands of acres in south central Idaho, partially destroying town of Lowman.
• 1990 -
  • Idaho Population: 1,006,749.
  • Idaho celebrates Statehood Centennial - July 3.
  • Senator James McClure retires from U.S. Senate.
  • Idaho State Senate split - 21 Democrats and 21 Republicans.
• 1991 -
  • Kirby Dam collapses near Atlanta, cutting off electrical power to residents and dumping arsenic, mercury and cadmium into the Middle Fork of the Boise River.
  • Drought persists through fifth consecutive year.
• 1992 -
  • Fire on the second and third floors of the State Capitol on January 1st caused 3.2 million dollars in damage.
  • Worst forest fire season in Idaho's recorded history.
  • Randy Weaver and Kevin Harris surrender to federal officials on August 31st following a shootout and eleven day standoff at Weaver's Boundary County cabin that left one U.S. deputy marshall and Weaver's wife and son dead.
  • Linda Copple Trout becomes the first woman appointed to the Idaho Supreme Court.
• 1993 -
  • Normal winter and spring precipitation help to alleviate the drought.
  • Kevin Harris acquitted of all charges and Randy Weaver convicted on minor charges following a 60-day federal trial stemming from the 1992 shootout with federal officials in Boundary County.
• 1994 -
  • Ezra Taft Benson, native of Whitney, Idaho, died on May 30.
  • Benson had served as U.S. Secretary of Agriculture from 1953 to 1961 and head of the Mormon Church since 1985.
  • Summer wildfires burn approximately 750,000 acres.
  • Picabo Street wins silver medal in downhill skiing during the Olympic games in Lillehammer, Norway.
  • Idaho ranks third nationwide in percentage population growth after the state added another 33,000 residents.
• 1995 -
  • Phil Batt sworn in as the first republican governor in twenty-five years.
  • Legislature creates the Department of Juvenile Justice.
  • Picabo Street becomes first American to win World Cup downhill title. 
  • Nuclear waste agreement signed.
  • First year of five years in a row of normal or above normal water/snowpack.
• 1996 -
  • Idaho suffered from severe flooding. President Clinton visited to discuss the problem.
• 1997 -
  • New Year's day floods in the Weiser and Payette River drainages of southwestern Idaho.
  • Town of Banks condemned by federal government following mudslides.
• 1997 - January 1 flooding caused severe problems in the town of Banks. The federal government condemned the city after the mudslides.
• 1998 - Picabo Street won a gold medal at the Winter Olympics in the giant slalom.
• 1999 - First shipment of nuclear waste left INEEL for permanent storage at the federal Waste Isolation Pilot Project in New Mexico.