Boulder is a city in Boulder County, Colorado, United States. According to the last census, the urban area has 94,673 inhabitants. The University of Colorado at Boulder, the leading university in Colorado, is located here. Boulder's altitude is 5,430 feet above sea level. Boulder is the eighth-biggest city in Colorado and the chief city in Boulder County.

Boulder is renowned for its dedication to maintaining space and calculating urban growth. Boulder has a standing as a stronghold of moderation in a mainly traditional state. Boulder, according to available data, has 39,596 houses, and 16,788 families dwelling in the city. The population concentration is 1,499.9/km (3,884.1/mi). At a normal concentration of 645.2/km (1,670.8/mi), there are 40,726 housing units. The population breakdown is 88.33% white, 1.22% black, 0.48% Native Americans, 4.02% Asian, 0.05% Pacific Islander, 3.50% from different races, and 2.40% from two or more ethnic groups. About 8.24% of the inhabitants are Hispanic of any ethnic group.

Of the 39,596 homes, 20.0% have children below the age of 18 living in them, 33.3% are married couples, 6.5% include a female occupant with no husband in attendance, and 57.6% do not have families in the truest sense of the term. Individuals comprise 33.7% of dwelling units, and 6.2% of houses somebody residing unaccompanied and is 65 years of age or older. The regular family volume is 2.20 and the normal family extent is 2.84.

Boulder is positioned in the Boulder Valley, where the Rocky Mountains cross the Great Plains. West of the city are spectacular slabs of sedimentary stone tilted up on the base of the mountains, called The Flatirons. The city has a total area of 65.7 sq km, out of which 63.1 sq km is land and 2.6 sq km of it is water.