New Castle County, Delaware On November 6, 1674, New Amstel was made dependent on New York Colony, and was renamed New Castle on November 11, 1674. On September 22, 1676, New Castle County was formally placed under the Duke of York's laws. It gained land from Upland County on November 12, 1678. On June 21, 1680, St. Jones County was carved from New Castle County. It is known today as Kent County, Delaware. On August 24, 1682, New Castle County, along with the rest of the surrounding land, was transferred from the Colony of New York to the possession of William Penn, who established
National Register of Historic Places listings in southern New Castle County, Delaware are located south of the Chesapeake and Delaware Canal and are listed here, including one site further designated as a National Historic Landmark. There are 84 sites in Wilmington, which are listed at National Register of Historic Places listings in Wilmington, Delaware. There are 220 sites in northern New Castle County outside Wilmington, which are listed at National Register of Historic Places listings in northern New Castle County, Delaware. Contents: Divisions in Delaware National Register of Historic Places listings in southern New Castle County, Delaware This is a list of the National Register of Historic Places listings in southern New