Thorndale is a census-designated place in Caln Township, Chester County, Pennsylvania, United States. The population was 3,407 at the 2010 census.

Caln Township is a township in Chester County, Pennsylvania, United States. The population was 14,428 at the 2020 census. The township was founded by settlers from Calne, Wiltshire in England in 1714; the relationship between Calne and Wiltshire continues in the present since the two are sister cities. Caln is a township of the First Class, and the governing body is a Board of Commissioners. The township also owns Ingleside Golf Club and over 200 acres (0.81 km2) of green space and parks.