The National Harbor of Refuge and Delaware Breakwater Historic District encompasses a series of seacoast breakwaters behind Cape Henlopen, Delaware that were built in a program to establish a shipping haven on a coastline that lacked safe harbors. The Harbor of Refuge is at the mouth of the Delaware Bay estuary where it opens into the Atlantic Ocean, at Lewes. The district is almost entirely offshore, only touching land at the former U.S. Coast Guard station. It was added to the National Register of Historic Places in 1989.