Lionville is a census-designated place (CDP) in Uwchlan Township, Chester County, Pennsylvania, United States. The population was 6,189 at the 2010 census. Prior to 2010 the CDP was recorded as Lionville-Marchwood. "Marchwood", however, refers only to the housing development begun in the early 1960s that is located south of the 100-113 intersection.Lionville is bisected by two major local highways, PA 100 and PA 113. The area contains residential neighborhoods, hotels, restaurants, and other businesses. The original name of the village was Welsh Pool, but to honor the local Red Lion Inn the name was changed to Lionville, since a borough of Red Lion, Pennsylvania, already existed. The area of Lionville along Village Avenue is a protected historic district. The Friends Meeting House was used as a hospital by the Continental Army during the American Revolutionary War.According to the United States Census Bureau, the CDP has a total area of 2.5 square miles (6.5 km2), all of it land.