Kilmarnock is a town in Lancaster and Northumberland counties in the U.S. state of Virginia. The population was 1,244 at the 2000 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.
Kilmarnock is located at 37°42′45″N 76°22′54″W / 37.7125°N 76.38167°W / 37.7125; -76.38167 (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) of it is land and 0.35% is water.