1968 Map of Seneca

About this map

The Potomac River carves a dramatic boundary through this 1960s survey, separating Montgomery County, Maryland, from the Virginia counties of Loudoun and Fairfax. This corridor is defined by the Chesapeake and Ohio Canal National Historical Park, where historical locks like Lock 24 and Lock 23 near Rushville trace the legacy of nineteenth-century river commerce. Further downstream, the river fragments into a series of significant landforms, including Watkins Island, Clagett Island, and Conn Island, leading toward the complex hydrology of Great Falls National Park.