Ellsworth Air Force Base (AFB) (IATA: RCA, ICAO: KRCA, FAA LID: RCA) is a United States Air Force base located about 10 miles (16 km) northeast of Rapid City, South Dakota, just north of the town of Box Elder.
According to the United States Census Bureau, the CDP has a total area of 1.9 mi² (4.9 km²), all land.
As of the census of 2000, there were 4,165 people, 1,056 households, and 991 families residing in the CDP. The population density was 2,217.8/ mi² (855.4/ km²). There were 1,076 housing units at an average density of 573.0/ mi² (221.0/ km²). The racial makeup of the CDP was 82.2% White, 6.7% Black or African American, 0.9% Native American, 2.3% Asian, 0.3% Pacific Islander, 2.6% from other races, and 5.1% from two or more races. Hispanic or Latino of any race were 6.6% of the population.
There were 1,056 households out of which 74.0% had children under the age of 18 living with them, 86.6% were married couples living together, 4.5% had a female householder with no husband present, and 6.1% were non-families. 4.5% of all households were made up of individuals, none of whom were 65 years of age or older. The average household size was 3.41 and the average family size was 3.51.
In the CDP, the population was spread out with 36.4% under the age of 18, 24.7% from 18 to 24, 36.3% from 25 to 44, 2.4% from 45 to 64, and 0.2% who were 65 years of age or older. The median age was 22 years. For every 100 females, there were 119.0 males. For every 100 females age 18 and over, there were 131.0 males.
The median income for a household in the CDP was $31,919, and the median income for a family was $31,941. Males have a median income of $20,721 versus $15,238 for females. The per capita income for the CDP was $11,362. About 3.4% of the population and 4.3% of the population were below the poverty line, including 3.9% of those under the age of 18 and none of those 65 and older.