Kilmarnock is a town in Lancaster and Northumberland counties in the U.S. Commonwealth of Virginia. The population was 1,487 at the 2010 census. It is located near the mouth of the Rappahannock River and is located within the Northern Neck George Washington Birthplace American Viticultural Area winemaking appellation. There is a small hospital in the town. Lancaster Middle School, grades 4–8, is also located in town. Approximately 500 students attend the school.
The town was named after Kilmarnock, in Scotland.
Kilmarnock is located at 37°42′45″N 76°22′54″W (37.712437, -76.381707).
According to the United States Census Bureau, the town has a total area of 2.9 square miles (7.4 km²), of which, 2.9 square miles (7.4 km²)is land and 0.35% is water.
Kilmarnock hosts the Holly Ball, a debutante ball founded in 1895, at the Indian Creek Yacht and Country Club every December.
At the 2000 census there were 1,244 people, 547 households, and 305 families living in the town. The population density was 435.6 people per square mile (167.9/km²).