Occoquan Historic District is a national historic district located at Occoquan, Prince William County, Virginia. It encompasses 60 contributing buildings in the town of Occoquan. The buildings are predominantly frame, two-story, residential structures although the earliest examples are constructed of stone or brick. The Ellicott's Mill House …Occoquan Historic District is a national historic district located at Occoquan, Prince William County, Virginia. It encompasses 60 contributing buildings in the town of Occoquan. The buildings are predominantly frame, two-story, residential structures although the earliest examples are constructed of stone or brick. The Ellicott's Mill House houses Historic Occoquan, Inc. The district also includes several notable non-residential buildings including the Hammill Hotel, Ebenezer Church, Methodist Church, and Crescent Lodge #3. Located in the district is the separately listed Rockledge.