Aurora is a home rule municipality located in Arapahoe, Adams, and Douglas counties, Colorado, United States. The city's population was 386,261 at the 2020 United States Census with 336,035 residing in Arapahoe County, 47,720 residing in Adams County, and 2,506 residing in Douglas County. Aurora is the third-most-populous city in the State of Colorado and the 52nd-most-populous city in the United States. Aurora is a principal city of the Denver–Aurora–Lakewood Metropolitan Statistical Area (MSA) and a major city of the Front Range Urban Corridor.

Buckley Space Force Base is a United States Space Force base in Aurora, Colorado named after United States Army Air Service First Lieutenant John Harold Buckley. The base is run by Space Base Delta 2, with major units including the U.S. Space Force's Space Delta 4, the Colorado Air National Guard's 140th Wing, the Denver Naval Operations Support Center, and the National Reconnaissance Office's Aerospace Data Facility-Colorado.