The University of Delaware Library has or provides access to a number of resources for information on historic structures.
Strengths are for the State of Delaware, particularly New Castle County.
The National Register of Historic Places, including more than 71,000 listings, is the Nation's official list of cultural resources worthy of preservation. You can look up historic places by state and county. The information you retrieve is minimal. After you determine that a property is on the National Register , you may be able to use the following resource. National Register of Historic Places.