Douglas County is the eighth most populous of the 64 counties of the State of Colorado of the United States. The county, sometimes nicknamed Dougco, is located midway between Colorado's two largest cities: Denver and Colorado Springs. The United States Census Bureau estimates that the county population was 263,621 in 2006, a 49.98% increase since U.S. Census 2000, making Douglas County one of the fastest growing counties in the United States. Douglas County is part of the Denver-Aurora Metropolitan Statistical Area and the Denver-Aurora-Boulder Combined Statistical Area. The county seat is Castle Rock, named after a small butte just north of the town. Castle Rock is located in the Interstate 25 corridor just east of the Front Range of the Rocky Mountains.
Douglas County is lightly wooded, mostly with ponderosa pine, with broken terrain characterized by mesas and small streams. Cherry Creek and Plum Creek rise in Douglas County and flow north toward Denver and into the South Platte River. Both were subject to flash flooding in the past, Plum Creek being partially responsible for the Denver flood of 1965. Cherry Creek is now dammed.
Residents generally commute to workplaces elsewhere in the metropolitan area outside of the county. Urbanization is gradually displacing the ranching economy of the county.
Douglas County has a comprehensive library system with a large local history section, the Douglas County History Research Center, at http://www.douglascountyhistory.org
Recreation trails in the county include:
There were 60,924 households out of which 47.2% had children under the age of 18 living with them, 73.8% were married couples living together, 5.7% had a female householder with no husband present, and 18.2% were non-families. 13.3% of all households were made up of individuals and 1.9% had someone living alone who was 65 years of age or older. The average household size was 2.88 and the average family size was 3.19.
In the county the population was spread out with 31.6% under the age of 18, 4.8% from 18 to 24, 37.9% from 25 to 44, 21.6% from 45 to 64, and 4.2% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 99.7 males. For every 100 females age 18 and over, there were 97.4 males.
The median income for a household in the county was $82,929, and the median income for a family was $88,482. Males had a median income of $60,729 versus $38,965 for females. The per capita income for the county was $34,848. About 1.6% of families and 2.1% of the population were below the poverty line, including 1.9% of those under age 18 and 3.7% of those age 65 or over.
Douglas County had the highest median household income of any county or statistical equivalent in 2000.
The University Center at Chaparral in Parker offers courses through Arapahoe Community College, University of Colorado at Denver, University College of the University of Denver, and the Douglas County School District.