Washington County Maryland (Historic Districts) has 22 places on the National Register of Historic Places including 6 places of National significance and 3 places of Statewide significance. Significant places include Antietam National Battlefield, Chesapeake and Ohio Canal National Historical Park, Chesapeake and Ohio Canal National Historical Park, Chesapeake and Ohio Canal National Historical Park and Chesapeake and Ohio Canal National Historical Park.
The famous person John Brown is associated with one of more of the Washington County historic places.
Some of the country's most noteable architects helped create the Washington County places including Benjamin Wright, George Burnap, Sims and Sims and William H. Lee. Prominent architectural styles found in Washington Country are Federal, Italianate and Greek Revival.