Boundary - Boulder

Boulder County is the sixth most populous of the 64 counties of the state of Colorado of the United States. The county seat is Boulder. The most populous municipality in the county and the county seat is the City of Boulder. Boulder County is coextensive with the Boulder Metropolitan Statistical Area, an Office of Management and Budget-designated metropolitan statistical area also used for statistical purposes by the Census Bureau.

The United States Census Bureau that the county population was 294,567 in 2010 census. This was a 8.4% between 2010 and 2000, but a gain of 3.95% since 2000 excluding the area transferred to the City and County of Broomfield. Boulder Metropolitan Statistical Area is the 161st most populous metropolitan statistical area in the United States.

The Boulder MSA together with the Denver-Aurora MSA, and the Greeley MSA comprise the Denver-Aurora-Boulder Combined Statistical Area.

Colorado (pronounced ⁱ/kɒləˈrædoʊ/) is the US state that encompasses most of the Southern Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is part of the Western United States, the Southwestern United States, and the Mountain States. Colorado is the 8th most extensive and the 22nd most populous of the 50 United States. The United States Census Bureau estimates that the population of Colorado was 5,116,796 on July 1, 2011, an increase of +1.74% since the 2010 United States Census.