The City of Castle Pines is a home rule city located in Douglas County, Colorado, United States. As of the 2010 census, the population of the city was 10,360. By 2013, the United States Census Bureau estimated the population to have increased to 10,726. The city is situated 19 miles (31 km) south-southeast of the Colorado State Capitol in Denver. The city is located north of the Town of Castle Rock and south of the City of Lone Tree, Colorado.
Castle Pines is located at 39°28′18″N 104°53′41″W / 39.471742°N 104.894827°W / 39.471742; -104.894827 (39.471742, -104.894827) at an elevation of 6,368 feet (1,941 m). Located on Interstate 25 in central Colorado, Castle Pines is 20 mi (32 km) south of downtown Denver and 43 mi (69 km) north of Colorado Springs.
The city lies in the Colorado Piedmont on the western edge of the Great Plains. Happy Canyon Creek runs north-northeast through the western part of the city, and Newlin Gulch and its tributary, South Newlin Gulch, run north-northeast and north, respectively, through the eastern part of the city. All three streams are part of the Cherry Creek watershed.
According to the United States Census Bureau, Castle Pines has a total area of 9.01 square miles (23.3 km), all of it land.
Lying within the Front Range Urban Corridor, the city is part of the greater Denver metropolitan area, and it borders two communities to its south: Castle Pines Village and Castle Rock, the county seat.
As of the 2010 census, there were 10,360 people, 3,493 households, and 2,928 families residing in the city. The population density was 1,149.8 people per square mile (444.6/km²). There were 3,637 housing units at an average density of 403.7 per square mile (156.1/km²). The racial makeup of the city was 92.6% White, 2.6% Asian, 1.1% African American, 0.2% American Indian, 0.1% Pacific Islander, 1.0% from other races, and 2.3% from two or more races. Hispanics and Latinos of any race were 5.5% of the population.
There were 3,493 households out of which 50.0% had children under the age of 18 living with them, 76.3% were married couples living together, 2.7% had a male householder with no wife present, 4.9% had a female householder with no husband present, and 16.2% were non-families. 13.0% of all households were made up of individuals, and 2.7% had someone living alone who was 65 years of age or older. The average household size was 2.97, and the average family size was 3.27.
In the city, the population was spread out with 33.6% under the age of 18, 3.8% from 18 to 24, 24.8% from 25 to 44, 30.2% from 45 to 64, and 7.6% who were 65 years of age or older. The median age was 39.5 years. The gender makeup of the city was 49.7% male and 50.3% female.
Castle Pines is one of the most affluent cities in the United States. The median income for a household in the city was $137,019, and the median income for a family was $147,473. Males had a median income of $118,235 versus $71,399 for females. The per capita income for the city was $49,702. About 0.9% of families and 1.7% of the population were below the poverty line, including 2.9% of those under age 18 and 0.0% of those age 65 or over.