The 2012 United States House of Representatives elections in Idaho were held on Tuesday, November 6, 2012 and elected two U.S. Representatives, one from each of the state's two congressional districts. The elections coincided with those of other federal and state offices, including a quadrennial presidential election. Candidate filing took place between February 27 and March 9, 2012. Primary elections were held on May 15, 2012.
Although Idaho's overall population grew by more than 20 percent during the period between 2000 and 2010, more significant growth elsewhere meant the state did not gain extra representation in the House of Representatives, instead remaining at two seats. The 2010 United States Census found that the population of the 1st district, which previously comprised the state's western and northern counties, as well as parts of Ada County including much of western Boise, had 116,278 more residents than the 2nd district, which included the rest of Boise, the Magic Valley region and the state's eastern counties. This shift in population meant that the 2nd district, currently represented by RepublicanMike Simpson, would include more of Ada County beginning in 2012 and up through the 2020 Congressional election.
In October 2011 the Idaho Commission on Redistricting approved by a 4-2 vote a Congressional district map which moved the district boundary in Boise west from Cole Road to Cloverdale Road. This placed almost all of Boise in the 2nd district, with only a few far western neighborhoods remaining in the 1st district. Other Ada County cities including Meridian, Eagle, Star, Kuna and Garden City remained in the 1st district. No changes were made to Congressional district boundaries outside Ada County.
On January 18, 2012, the Idaho Supreme Court struck down the redistricting plan approved by the Commission on Redistricting in October 2011 on the grounds that it violated the Idaho Constitution. The commission reconvened on January 26, 2012, to make necessary revisions which were approved the following day. The commission's January 2012 changes dealt solely with state legislative districts, leaving the original Congressional redistricting plan intact.