Radnor is an unincorporated community in Radnor Township of Delaware County and Tredyffrin Township of Chester County in the U.S. state of Pennsylvania. It lies near the communities of Villanova and St. Davids, and is served by the SEPTA Paoli/Thorndale Line of Regional Rail and the Norristown High Speed Line. Once a country retreat for Philadelphia's most prominent families, the community includes the estates of Woodcrest, Walmarthon, Bolingbroke, Rock Rose, and The Woods. Nearby places of worship include St. David's Episcopal Church, whose graveyard and buildings (begun in 1715) are listed on the National Register of Historic Places.