Thorndale is a census-designated place in Caln Township, Chester County, Pennsylvania, United States.

Thorndale is the commercial and administrative center of Caln Township.

Many of Thorndale's old houses fell into disrepair from the late 1990s to present and have been torn down and replaced with new businesses.

Thorndale is historically notable for containing a summer house of U.S. President James Buchanan, which still stands and has been incorporated into a golf course and turned into a restaurant.

[1] According to the U.S. Census Bureau, Thorndale has a total area of 1.8 square miles (4.7 km2), of which 0.55% is water.

22.3% of all households were made up of individuals, and 5.4% had someone living alone who was 65 years of age or older.