The district was created in 1983 as a result of the redistricting cycle after the 1980 census, and was originally a classic suburban Republican bastion; this was once the safest seat for Colorado Republicans outside of Colorado Springs. However, changing demographics in the Front Range, especially in Arapahoe County which went from a traditional conservative suburban/exurban stronghold to a densely populated, ethnically and culturally diverse Democratic-leaning inner suburban county, has made these suburban areas much friendlier to Democrats. The 2010 redistricting shifted the more rural, GOP-dominated sections of the district to the nearby 4th and added heavily populated and Democratic parts of Aurora, turning the 6th district into a Democratic-leaning swing district. However, Republicans are still competitive downballot, and the Democratic strength was limited to western Arapahoe County for much of its history, as the components of Douglas County and Adams County in the 6th were still Republican leaning: this changed in 2020, as Joe Biden and Representative Jason Crow won all county areas in the district.
After 2020 redistricting, the 6th became a purely inner suburban district anchored in western Arapahoe County, although small parts of Jefferson, Douglas, and Adams Counties were included as well to completely take in the cities of Littleton and Aurora. A small portion of the City and County of Denver near Four Square Mile is also located in the district: this version of the district is now fairly safe for Democrats with a PVI of D+11.
History
1990s
Following the 1990 U.S. census and associated realignment of Colorado congressional districts, the 6th congressional district consisted of portions of Arapahoe and Jefferson counties.
2000s
Following the 2000 U.S. census and associated realignment of Colorado congressional districts, the 6th congressional district consisted of Douglas and Elbert counties as well as portions of Arapahoe, Jefferson, and Park counties.
2010s
During the 2010 Colorado Redistricting, the 6th congressional district lost most of its previous area; the district now consisted of the western portions of Arapahoe and Adams counties plus the community of Highlands Ranch in Douglas County and a very little part of Jefferson County.
Suburban in character, this ethnically and economically diverse district takes in Denver's southern and eastern suburbs and is now fairly Democratic, despite historically being a Republican district.
Aurora, a diverse city with 21% foreign-born residents makes up the base of the population: while the city generally votes to the left and is a suburban stronghold for Colorado Democrats, it also provided enough support for Republican Mike Coffman to hold the district for a decade.
The suburbs to Denver's south side in the district are a mixed bag - Greenwood Village and Cherry Hills Village have a large amount of registered Republicans, however the Republicans here are mainly economically conservative and much more moderate socially compared to the rest of the state. Centennial and Littleton have historically tended to vote Republican but have voted Democratic since 2016: Englewood and Sheridan, being closer socially and economically to nearby Denver are safe for the Democrats, however they do not make up a large part of the district's population.
Composition
For the 118th and successive Congresses (based on redistricting following the 2020 census), the district contains all or portions of the following counties and communities:
Aurora (shared with Adams and Arapahoe counties), Bow Mar (shared with Arapahoe County), Columbine (shared with Arapahoe County), Ken Caryl, Littleton (shared with Arapahoe and Jefferson counties)
