Lionville is a census-designated place (CDP) in Uwchlan Township, Chester County, Pennsylvania, United States.

"Marchwood", however, refers only to the housing development begun in the early 1960s that is located south of the 100-113 intersection.

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.

Lionville has an independent ZIP Code and post office, but it has never had mail delivery.

Many of the long-term residents who picked up mail at the now-closed general store or fire station locations now use a Downingtown address.

[4] According to the U.S. Census Bureau, the CDP has a total area of 2.5 square miles (6.5 km2), all land.