The United States Office of Management and Budget has defined the 12-county Denver–Aurora, CO Combined Statistical Area comprising the Denver–Aurora–Lakewood, CO Metropolitan Statistical Area, the Boulder, CO Metropolitan Statistical Area, and the Greeley, CO Metropolitan Statistical Area.

[1] The United States Census Bureau estimates that the population was 3,214,218 as of July 1, 2012, an increase of +3.99% since the 2010 United States Census, and ranking as the 16th most populous metropolitan combined statistical area and the 17th most populous primary statistical area of the United States.

[2][3] The population estimate for 2020 was 3,652,385.

[4] The Denver–Aurora CSA comprises the Denver–Aurora–Lakewood, CO Metropolitan Statistical Area, the Boulder, CO Metropolitan Statistical Area, and the Greeley, CO Metropolitan Statistical Area.

The table below includes the following information: The Denver–Aurora, CO CSA includes the following jurisdictions in the State of Colorado: