Yorklyn is an unincorporated community in northern New Castle County, Delaware, United States. It lies along Delaware Route 82 northwest of the city of Wilmington, the county seat of New Castle County. Its elevation is 174 feet (53 m). Although it is unincorporated, it has a post office, with the ZIP code of 19736.
Yorklyn is home to Auburn Valley State Park which includes the Friends of Auburn Heights Preserve and Marshall Steam Museum with the largest operating collection of Stanley Steamer cars in the world. Also nearby is Ashland Nature Center and the Center for the Creative Arts along with the Yorklyn Recreation Center, commonly referred to as the Yorklyn pool, which houses two pools, tennis courts, and basketball courts.
The Auburn Mills Historic District, Garrett Snuff Mills Historic District, Graves Mill Historic District, and Garrett Snuff Mill are listed on the National Register of Historic Places.
The National Vulcanized Fiber company was headquartered in Yorklyn, however since bankruptcy in 2008 the plant has been largely torn down and the land purchased by the State of Delaware for Auburn Heights Preserve, a Delaware State Park. Plans call for restoring the original Marshall Brothers Mill into a museum and using some of the original NVF buildings for other uses.