Centennial is a home rule municipality located in Arapahoe County, Colorado, United States. The city population was 108,418 at the 2020 United States Census, making Centennial the 11th most populous municipality in Colorado. Centennial is a part of the Denver–Aurora–Lakewood, CO Metropolitan Statistical Area and the Front Range Urban Corridor.

Arapahoe County is a county located in the U.S. state of Colorado. As of the 2020 census, its population was 655,070, making it the third-most populous county in Colorado. The county seat is Littleton, and the most populous city is Aurora. The county was named for the Arapaho Native American tribe, who once lived in the region.