Bầu cử tổng thống Hoa Kỳ tại Idaho năm 1964

The 1964 United States presidential election in Idaho took place on November 3, 1964, as part of the 1964 United States presidential election, which was held throughout all 50 states and Washington, D.C. Voters chose four representatives, or electors to the Electoral College, who voted for president and vice president.

Idaho was one of 44 states carried by incumbent President Lyndon B. Johnson amidst his national landslide. However, it was Johnson's narrowest victory in the election. He carried the state by a margin of 5,363 votes, or 1.83%, making Idaho about 20.75% more Republican than the nation. Johnson's strongest performances were in Clearwater and Lewis Counties in the heavily unionized Idaho Panhandle logging country, where he took over 76% of the vote. Goldwater's strongest performance was in ancestrally Republican Jerome County, with 63% of the vote. While Johnson carried slightly over half of the state's 44 counties, Goldwater carried most of the more populous counties (such as Ada, Bonneville, Canyon and Twin Falls), thus keeping the vote close.

As of 2024, this is the only presidential race since 1948 where Idaho voted Democrat, and although Goldwater lost, this election continued the solidification of Idaho as a Republican stronghold. The state trended 13.02% Republican relative to the national swing. Kennedy had lost the state by 7.5% in 1960, but that was in a nearly tied national environment, while Johnson only narrowly won it amidst a 23-point Democratic landslide nationwide. In nine counties, Goldwater earned a higher share of the vote than Richard Nixon had in 1960 – a result observed in only nine other counties outside antebellum slave states. Apart from heavily Catholic Emmons County, North Dakota, Camas and Custer in Idaho were the solitary counties outside antebellum slave states to vote for Kennedy in 1960 and Goldwater in 1964.

No Democratic presidential nominee since Johnson in 1964 has been able to get even 40% of Idaho's popular vote, while the only Republicans to fail to pass 55% have been George H. W. Bush in 1992 and Bob Dole in 1996, in which Ross Perot's and Bo Gritz's third-party candidacies played a part.