Colorado's 1st congressional district is a congressional district in the U.S. state of Colorado based primarily in the City and County of Denver in the central part of the state. The district includes all of the City and County of Denver, and the Denver enclaves of Glendale and Holly Hills.

Diana Louise DeGette is an American lawyer and politician serving as the U.S. representative for Colorado's 1st congressional district since 1997. A member of the Democratic Party, her district is based in Denver. DeGette was a Chief Deputy Whip from 2005 to 2019 and is the dean of Colorado's congressional delegation; she served as the Colorado State Representative for the 6th district from 1993 until her election to the U.S. House.