This timeline is a chronology of significant events in the history of the U.S. State of Idaho and the historical area now occupied by the state. __NOTOC__
2020s YearDateEvent2020November 3In the 2020 General Election, Idaho voters elect four U.S. Presidential Electors for President Donald Trump, re-elect Jim Risch as junior U.S. Senator, and re-elect Russ Fulcher and Mike Simpson as U.S. Representatives. Republicans retain control of the Idaho Legislature.April 1The 2020 United States census enumerates the population of the State of Idaho, estimated to be about 1,824,000.
2010s YearDateEvent2019January 7Brad Little assumes office as the 33rd Governor of the State of Idaho.2010April 1The 2010 United States census enumerates the population of the State of Idaho, later determined to be 1,567,582, an increase of 21.1% since the 2000 United States census. Idaho remains the 39th most populous of the 50 U.S. state.
2000s YearDateEvent2009March 30U.S. President Barack Obama signs An Act to designate certain land as components of the National Wilderness Preservation System, to authorize certain programs and activities in the Department of the Interior and the Department of Agriculture, and for other purposes, creating the Pacific Northwest National Scenic Trail and the Ice Age Floods National Geologic Trail.January 3Jim Risch assumes office as the junior United States senator for the State of Idaho.2008May 8U.S. President George W. Bush signs An Act To modify the boundary of the Minidoka Internment National Monument, to establish the Minidoka National Historic Site, to authorize the Secretary of the Interior to convey certain land and improvements of the Gooding Division of the Minidoka Project, Idaho, and for other purposes, redesignating Minidoka Internment National Monument as Minidoka National Historic Site.2007January 1Butch Otter assumes office as the 32nd Governor of the State of Idaho.2006May 26Lieutenant Governor Jim Risch assumes office as the 31st Governor of the State of Idaho upon the resignation of Governor Kempthorne.2002August 21U.S. President George W. Bush signs An Act To redesignate certain lands within the Craters of the Moon National Monument, and for other purposes, creating Craters of the Moon National Preserve.2001January 17U.S. President Bill Clinton issues a public land order creating Minidoka Internment National Monument.2000April 1The 2000 United States census enumerates the population of the State of Idaho, later determined to be 1,293,953, an increase of 28.5% since the 1990 United States census. Idaho becomes the 39th most populous of the 50 U.S. states.
1990s YearDateEvent1999January 4Dirk Kempthorne assumes office as the 30th Governor of the State of Idaho.January 3Mike Crapo assumes office as the junior United States senator for the State of Idaho.1995January 2Phil Batt assumes office as the 29th Governor of the State of Idaho.1990April 1The 1990 United States census enumerates the population of the State of Idaho, later determined to be 1,006,749, an increase of 6.7% since the 1980 United States census. Idaho becomes the 42nd most populous of the 50 U.S. states and loses its 2nd Congressional District.
1980s YearDateEvent1987January 5Cecil Andrus assumes office as the 28th Governor of the State of Idaho.1988November 10U.S. President Ronald Reagan signs An Act To provide for the designation and conservation of certain lands in the States of Arizona and Idaho, and for other purposes, creating City of Rocks National Reserve and Hagerman Fossil Beds National Monument.1980April 1The 1980 United States census enumerates the population of the State of Idaho, later determined to be 943,935, an increase of 32.5% since the 1970 United States census. Idaho becomes the 41st most populous of the 50 U.S. states.
1970s YearDateEvent1978November 10U.S. President Jimmy Carter signs the National Parks and Recreation Act of 1978 authorizing the Lewis and Clark National Historic Trail and the Continental Divide National Scenic Trail.October 9The United Nations Educational, Scientific and Cultural Organization (UNESCO) designates Yellowstone National Park as one of the first 12 World Heritage Sites.1977January 23Cecil Andrus assumes office as the 42nd United States Secretary of the Interior.Lieutenant Governor John V. Evans assumes office as the 27th Governor of the State of Idaho upon the resignation of Governor Andrus1976July 4The State of Idaho celebrates the Bicentennial of the United States of America.1971January 4Cecil Andrus assumes office as the 26th Governor of the State of Idaho.1970April 1The 1970 United States census enumerates the population of the State of Idaho, later determined to be 712,567, an increase of 6.8% since the 1960 United States census. Idaho remains the 42nd most populous of the 50 U.S. states.
1960s YearDateEvent1968December 2U.S. President Lyndon B. Johnson signs An Act to establish a national trails system, and for other purposes, creating the National Trails System.1967January 2Don Samuelson assumes office as the 25th Governor of the State of Idaho.1965May 15U.S. President Lyndon B. Johnson signs An Act to authorize the Secretary of the Interior to designate the Nez Perce National historical Park in the State of Idaho, and for other purposes, creating Nez Perce National Historical Park.1960April 1The 1960 United States census enumerates the population of the State of Idaho, later determined to be 667,191, an increase of 13.3% since the 1950 United States census. Idaho becomes the 42nd most populous of the 50 U.S. states.
1950s YearDateEvent1955January 3Robert E. Smylie assumes office as the 24th Governor of the State of Idaho.1954May 19U.S. President Dwight D. Eisenhower issues Public Land Order 965 splitting Cabinet National Forest among Kaniksu National Forest, Kootenai National Forest, and Lolo National Forest.1953October 23U.S. President Dwight D. Eisenhower issues Public Land Order 923 splitting Minidoka National Forest between Sawtooth National Forest and Salmon National Forest.1951January 1Len Jordan assumes office as the 23rd Governor of the State of Idaho.1950April 1The 1950 United States census enumerates the population of the State of Idaho, later determined to be 588,637, an increase of 12.1% since the 1940 United States census. Idaho becomes the 43rd most populous of the 48 U.S. states.
1940s YearDateEvent1947January 6C.A. Robins assumes office as the 22nd Governor of the State of Idaho.1945November 17Lieutenant Governor Arnold Williams assumes office as the 21st Governor of the State of Idaho upon the resignation of Governor Gossett.September 2World War II ends as the Empire of Japan formally surrenders.May 8The war in Europe ends as the Greater German Empire formally surrenders.January 1Charles C. Gossett assumes office as the 20th Governor of the State of Idaho.1943January 4C.A. Bottolfsen assumes office as the 19th Governor of the State of Idaho.1941December 11The United States declares war on the German Reich and the Italian Empire.December 8The United States declares war on the Empire of Japan and enters World War II.January 6Chase A. Clark assumes office as the 18th Governor of the State of Idaho.1940April 1The 1940 United States census enumerates the population of the State of Idaho, later determined to be 524,873, an increase of 17.9% since the 1930 United States census. Idaho remains the 42nd most populous of the 48 U.S. states.
1930s YearDateEvent1939January 2C.A. Bottolfsen assumes office as the 17th Governor of the State of Idaho.1938October 8U.S. President Franklin D. Roosevelt issues Executive Order 7986 splitting Lemhi National Forest between Challis National Forest and Salmon National Forest.1937July 22U.S. President Franklin D. Roosevelt signs An Act to create the Farmers' Home Corporation, to promote more secure occupancy of farms and farm homes, to correct the economic instability resulting from some present forms of farm tenancy, and for other purposes, also known as the Bankhead-Jones Farm Tenant Act.January 4Barzilla W. Clark assumes office as the 16th Governor of the State of Idaho.1934October 29U.S. President Franklin D. Roosevelt issues Executive Order 6889 splitting Selway National Forest among Bitterroot National Forest, Clearwater National Forest, Nezperce National Forest, and Kaniksu National Forest.1933September 30U.S. President Franklin D. Roosevelt issues Executive Order 6303 merging Pend Oreille National Forest into Kaniksu National Forest.1931January 5C. Ben Ross assumes office as the 15th Governor of the State of Idaho.1930April 1The 1930 United States census enumerates the population of the State of Idaho, later determined to be 445,032, an increase of 3.0% since the 1920 United States census. Idaho remains the 42nd most populous of the 48 U.S. states.
1920s YearDateEvent1927January 3H.C. Baldridge assumes office as the 14th Governor of the State of Idaho.1924June 2U.S. President Calvin Coolidge signs An Act To authorize the Secretary of the Interior to issue certificates of citizenship to Indians, also known as the Indian Citizenship Act of 1924, finally granting full United States Citizenship to all Native Americans born in the United States.May 2U.S. President Calvin Coolidge issues an executive order creating Craters of the Moon National Monument.1923January 1Charles C. Moore assumes office as the 13th Governor of the State of Idaho.1920April 1The 1920 United States census enumerates the population of the State of Idaho, later determined to be 431,866, an increase of 32.6% since the 1910 United States census. Idaho becomes the 42nd most populous of the 48 U.S. states.
1910s