The 2014 United States Senate election in Colorado was held on November 4, 2014, to elect a member of the United States Senate to represent the State of Colorado, concurrently with the election of the Governor of Colorado, other elections to the United States Senate, elections to the United States House of Representatives, and various state and local elections. Incumbent Democratic Senator Mark Udall ran for re-election to a second term, but narrowly lost to Republican U.S. Representative Cory Gardner by a margin of 1.9 percent.
Despite Gardner's win however, with slightly over 48% of the vote, it is the lowest a winning Republican had received in the Class 2 Senate seat since 1918. As of , this is the last time that a Republican has won a U.S. Senate race in Colorado.
Mark Udall was the only Democrat to file to run, and thus at the Democratic state assembly on April 12, 2014, he was renominated unopposed.
At the Republican state assembly on April 12, 2014, Cory Gardner received 73% of the votes of over 3,900 delegates. Neither Randy Baumgardner nor Tom Janich received the required 30% to make the ballot and thus Gardner received the party's nomination.
Counties that flipped from Democratic to Republican
Gardner won four of seven congressional districts.
Official campaign websites (archived)