Quantico is the site of one of the largest US Marine Corps bases in the world. It is the site of the Marine Corps Combat Development Command, and both the United States Drug Enforcement Administration's training academy and the FBI Academy are located on the base. A replica of the Marine Corps War Memorial stands in the entrance to the base. (The original stands at the north end of Arlington National Cemetery.)
As of the census of 2000, there are 561 people, 295 households, and 107 families residing in the town. The population density is 3,094.3/km² (7,811.2/mi²). There are 359 housing units at an average density of 1,980.2/km² (4,998.6/mi²). The racial makeup of the town is 61.32% White, 20.32% African American, 0.36% Native American, 10.16% Asian, 0.00% Pacific Islander, 2.32% from other races, and 5.53% from two or more races. 5.53% of the population are Hispanic or Latino of any race.
There are 295 households out of which 19.7% have children under the age of 18 living with them, 21.4% are married couples living together, 11.2% have a female householder with no husband present, and 63.4% are non-families. 53.2% of all households are made up of individuals and 9.2% have someone living alone who is 65 years of age or older. The average household size is 1.90 and the average family size is 3.02.
In the town the population is spread out with 20.9% under the age of 18, 11.6% from 18 to 24, 39.8% from 25 to 44, 19.4% from 45 to 64, and 8.4% who are 65 years of age or older. The median age is 35 years. For every 100 females there are 122.6 males. For every 100 females age 18 and over, there are 130.1 males.
The median income for a household in the town is $26,250, and the median income for a family is $27,596. Males have a median income of $29,615 versus $23,125 for females. The per capita income for the town is $19,087. 21.4% of the population and 22.4% of families are below the poverty line. Out of the total people living in poverty, 39.4% are under the age of 18 and 0.0% are 65 or older.