Aberdeen Proving Ground occupies more than 72,500 acres. Its northernmost point is marked by the confluence of the Susquehanna River and Chesapeake Bay. On the south it is bordered by the Gunpowder River.
Other parts of the proving ground not attached to the main installation includes the Churchville Test Site in Harford County and Carroll Island and Graces Quarters in Baltimore County, Maryland.
The United States Census has defined a census designated place (CDP) called Aberdeen Proving Ground which is a subset of the Army installation.
As of 2000, there are 3,116 people, 805 households, and 763 families residing in the CDP. The population density is 105.8/km² (274.1/mi²). There are 902 housing units at an average density of 30.6/km² (79.3/mi²). The racial makeup of the CDP is 50.48% White, 34.60% African American, 0.64% Native American, 3.11% Asian, 1.25% Pacific Islander, 5.68% from other races, and 4.24% from two or more races. 11.20% of the population are Hispanic or Latino of any race.
There are 805 households in the CDP, of which 78.0% have children under the age of 18 living with them, 84.1% are married couples living together, 8.0% have a female householder with no husband present, and 5.2% are non-families. 4.3% of all households are made up of individuals and 0.0% have someone living alone who is 65 years of age or older. The average household size is 3.52 and the average family size is 3.63.
In the CDP the population is spread out with 40.1% under the age of 18, 10.3% from 18 to 24, 44.9% from 25 to 44, 4.4% from 45 to 64, and 0.2% who are 65 years of age or older. The median age is 25 years. For every 100 females there are 113.9 males. For every 100 females age 18 and over, there are 117.6 males.
The median income for a household in the CDP is $38,875, and the median income for a family is $40,306. Males have a median income of $26,943 versus $26,194 for females. The per capita income for the CDP is $12,808. 5.6% of the population and 4.2% of families are below the poverty line. Out of the total people living in poverty, 6.4% are under the age of 18 and 0.0% are 65 or older.