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). It has a post office with the ZIP code 19736. 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.