Lexington Park is a census-designated place (CDP) in St. Mary's County, Maryland, United States, and the principal community of the Lexington Park, Maryland Micropolitan Statistical Area. The population was 11,626 at the 2010 census.
Archeological research in the county has shown that Native American peoples inhabited the area for at least 10,000 years. At the time of the arrival of the first colonists, the area was inhabited by the Yaocomico branch of the Piscataway Indian Nation. The Piscataway Nation, although fragmented, still exists today, and has small communities and cultural centers in other parts of the county.
The area was expanded into by "planters" (mostly tobacco farmers) who moved into the area as the original settlement in St. Mary's City grew. Early plantations were first farmed by indentured and free labor, but in the late 1600s slavery began to establish itself in Maryland and the character of farming changed due to this. Wealth was concentrated in very few hands and small free farmers and laborers were pushed out or "down" (into poverty) due to competition with slave labor.