About the Potomac Basin

Potomac River Basin Drinking Water Source Protection Partnership

The Potomac River basin stretches across parts of Maryland, Pennsylvania, Virginia, and West Virginia, as well as the District of Columbia. Encompassing 14,670 square miles, it includes all of the land area where water drains toward the mouth of the Potomac. Learn more about the Potomac watershed from the Interstate Commission on the Potomac River Basin.

Water Quality Information

Maps

Potomac watershed and major streams
Potomac watershed and major streams – click for larger view or download.

Land Use Map - 2006 Data - Image
Land use, using 2006 data – click for larger view or download.

View additional maps.