page_title: Potomac River
section_title: Tidal Potomac
hierarchical_section_title: Potomac River / Additional images / Tidal Potomac
caption_attribution_description: View of the Potomac River from the Mount Vernon plantation, Virginia.
context_page_description: The Potomac River is found within the Mid-Atlantic region of the United States and flows from the Potomac Highlands into the Chesapeake Bay. The river is approximately 405 miles long, with a drainage area of about 14,700 square miles. In terms of area, this makes the Potomac River the fourth largest river along the Atlantic coast of the United States and the 21st largest in the United States. Over 5 million people live within the Potomac watershed.
  The river forms part of the borders between Maryland and Washington, D.C., on the left descending bank and West Virginia and Virginia on the river's right descending bank. The majority of the lower Potomac River is part of Maryland. Exceptions include a small tidal portion within the District of Columbia, and the border with Virginia being delineated from "point to point". Except for a small portion of its headwaters in West Virginia, the North Branch Potomac River is considered part of Maryland to the low water mark on the opposite bank. The South Branch Potomac River lies completely within the state of West Virginia except for its headwaters, which lie in Virginia.
caption: View of the Potomac from Mount Vernon
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