While the name "Mount Vernon"—drawn from the Mount Vernon plantation, the home of George Washington located south of Alexandria—is often used locally to refer to the entire unincorporated area between Old Town Alexandria and Fort Belvoir, Mount Vernon as defined by the Census Bureau encompasses only the portion bounded by the Potomac River to the south, Fort Belvoir to the west, U.S. Route 1 to the north, and Little Hunting Creek to the east.
Beginning with the 2010 United States Census, the U.S. Census Bureau defined the portion of Mount Vernon north of U.S. Route 1 as a separate CDP, Woodlawn, reducing Mount Vernon's land area by approximately a third and its population by more than half.
Mount Vernon is located at  Located on U.S. Route 1 in Northern Virginia, Mount Vernon is 13 miles (21 km) south-southwest of downtown Washington, D.C. and 13 miles (21 km) southeast of Fairfax, the county seat.(38.7351590, −77.0953670) at an elevation of 79 feet (24 m).
Mount Vernon sits on the Atlantic Coastal Plain on the north side of the Potomac River. Two small tributaries of the river flow south through the CDP: Dogue Creek runs through the western part of the CDP, and Little Hunting Creek forms the CDP's eastern border.
As a suburb of Washington, D.C., Mount Vernon is a part of both the Washington Metropolitan Area and the larger Baltimore-Washington Metropolitan Area. It borders other Washington suburbs on all sides, including: Woodlawn and Hybla Valley to the north, Fort Hunt to the east, Accokeek and Bryans Road, Maryland across the Potomac River to the southeast, and Fort Belvoir to the west.
|* U.S. Decennial Census|
As of the census of 2000, there were 28,582 people, 10,575 households, and 7,487 families residing in the CDP. The population density was 1,450.1/km2 (3,755.8/sq mi). There were 10,926 housing units at an average density of 1,435.7/sq mi (554.3/km2). The racial makeup of the CDP was 54.42% White, 27.65% African American, 0.33% Native American, 6.33% Asian, 0.13% Pacific Islander, 6.87% from other races, and 4.26% from two or more races. Hispanic or Latino of any race were 14.50% of the population.
There were 10,575 households out of which 34.4% had children under the age of 18 living with them, 51.0% were married couples living together, 15.0% had a female householder with no husband present, and 29.2% were non-families. 22.6% of all households were made up of individuals and 4.4% had someone living alone who was 65 years of age or older. The average household size was 2.70 and the average family size was 3.16.
In the CDP, the population was spread out with 26.3% under the age of 18, 7.9% from 18 to 24, 32.4% from 25 to 44, 24.4% from 45 to 64, and 9.0% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 94.3 males. For every 100 females age 18 and over, there were 90.8 males.
The median income for a household in the CDP was $61,119, and the median income for a family was $67,892. Males had a median income of $42,049 versus $33,543 for females. The per capita income for the CDP was $29,299. About 5.3% of families and 7.0% of the population were below the poverty line, including 9.7% of those under age 18 and 2.4% of those age 65 or over.
Other notable individuals who were born in and/or have lived in Mount Vernon include: