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 northern New Castle County, Delaware National Register of Historic Places listings in northern New Castle County, Delaware This is a list of the National Register of Historic Places listings in northern New Castle County, Delaware. This is intended to be a complete list of the properties and districts on National Register of Historic Places in New Castle County, Delaware north of the Chesapeake and Delaware Canal, excluding the city of Wilmington. The locations of National Register properties and districts for which the latitude and longitude coordinates are included below, may be seen in a map. There are 387 properties and districts listed on the National