Boulder (40°1'N 105°16'W, Mountain Time Zone) is a city located in Boulder County, Colorado, United States. As of the 2000 census, the city had a total population of 94,673. It is home to the University of Colorado at Boulder, the largest university in Colorado. Boulder's elevation is 5,430 feet (1,655 meters) and is 35 miles (50 km) northwest of Denver. Boulder has the eighth greatest population among Colorado's cities and is the largest city and county seat of Boulder County.
Boulder is located in Boulder Valley where the Rocky Mountains meet the Great Plains. Just west of the city are imposing slabs of sedimentary stone tilted up on the foothills, known as The Flatirons. These are iconic of Boulder and often appear on city-related paraphernalia.
According to the United States Census Bureau, the city has a total area of 65.7 km2 (25.4 mi2). 63.1 km2 (24.4 mi2) of it is land and 2.6 km2 (1.0 mi2) of it is water. The total area is 3.94% water.
As of the census of 2000, there are 94,673 people, 39,596 households, and 16,788 families residing in the city. The population density is 1,499.9/km2 (3,884.1/mi2), making Boulder's population density higher than Denver's and among the highest in the state: of Colorado's twenty-one largest cities, only Englewood and Northglenn (two close-in Denver suburbs) have greater population densities. There are 40,726 housing units at an average density of 645.2/km2 (1,670.8/mi2). The racial makeup of the city is 88.33% White, 1.22% Black or African American, 0.48% Native American, 4.02% Asian, 0.05% Pacific Islander, 3.50% from other races, and 2.40% from two or more races. 8.24% of the population are Hispanic or Latino of any race.
There are 39,596 households out of which 20.0% have children under the age of 18 living with them, 33.3% are married couples living together, 6.5% have a female householder with no husband present, and 57.6% are non-families. 33.7% of all households are made up of individuals and 6.2% have someone living alone who is 65 years of age or older. The average household size is 2.20 and the average family size is 2.84.
Boulder's population is younger than the national average, largely due to the presence of university students. The median age is 29 years compared to the U.S. median of 35.1 years. In Boulder, 14.8% of the resident are under the age of 18, 25.9% from 18 to 24, 33.0% from 25 to 44, 18.4% from 45 to 64, and 7.8% are 65 years of age or older. For every 100 females there are 106.8 males. For every 100 females age 18 and older, there are 107.4 males.
The median household income in Boulder is $44,748, and the median family income is $70,257 which is more than $20,000 above the U.S. average. Males have a median income of $41,829 versus $32,100 for females. The per capita income for the city is $27,262. 17.4% of the population and 6.4% of families are below the poverty line. Out of the total population, 10.4% of those under the age of 18 and 6.5% of those 65 and older are living below the poverty line.
Boulder housing is expensive for the area. In 2000, the median value of a single-family owner-occupied home in Boulder was $304,700; the median value for all such homes in the United States was $119,600.