Potomac River
The Potomac River (/pəˈtoʊmək/ ⓘ) is a major river in the Mid-Atlantic region of the United States that flows from the Potomac Highlands in West Virginia to the Chesapeake Bay in Maryland. It is 405 miles (652 km) long, with a drainage area of 14,700 square miles (38,000 km2), and is the fourth-largest river along the East Coast of the United States and the 21st-largest in the United States. More than 5 million people live within its watershed.
| Potomac River | |
|---|---|
The Potomac River watershed covers the District of Columbia and parts of four states | |
| Native name | Patawomeck (Algonquian languages) |
| Location | |
| Country | United States |
| State | West Virginia, Maryland, Virginia, District of Columbia |
| Cities | Cumberland, MD; Harpers Ferry, WV; Washington, D.C.; Alexandria, VA |
| Physical characteristics | |
| Source | North Branch |
| • location | Fairfax Stone, Preston County, West Virginia |
| • coordinates | 39°11′43″N 79°29′28″W |
| • elevation | 3,060 ft (930 m) |
| 2nd source | South Branch |
| • location | Near Monterey, Highland County, Virginia |
| • coordinates | 38°25′30″N 79°36′27″W |
| Source confluence | |
| • location | Green Spring, West Virginia |
| • coordinates | 39°31′39″N 78°35′15″W |
| Mouth | Chesapeake Bay |
• location | St. Mary's County, Maryland/Northumberland County, Virginia, United States |
• coordinates | 38°00′00″N 76°20′06″W |
• elevation | 0 ft (0 m) |
| Length | 405 mi (652 km) |
| Basin size | 14,700 sq mi (38,000 km2) |
| Discharge | |
| • location | Little Falls, near Washington, D.C. (non-tidal; water years: 1931–2018) |
| • average | 11,498 cu ft/s (325.6 m3/s) (1931–2018) |
| • minimum | 4,017 cu ft/s (113.7 m3/s) (2002) |
| • maximum | 484,000 cu ft/s (13,700 m3/s) (1936) |
| Discharge | |
| • location | Point of Rocks, Maryland |
| • average | 9,504 cu ft/s (269.1 m3/s) |
| Discharge | |
| • location | Hancock, Maryland |
| • average | 4,168 cu ft/s (118.0 m3/s) |
| Discharge | |
| • location | Paw Paw, West Virginia |
| • average | 3,376 cu ft/s (95.6 m3/s) |
| Basin features | |
| Tributaries | |
| • left | Conococheague Creek, Antietam Creek, Monocacy River, Rock Creek, Anacostia River |
| • right | Cacapon River, Shenandoah River, Goose Creek, Occoquan River, Wicomico River |
| Waterfalls | Great Falls, Little Falls |
| ------------------------------------------------------------------ Note: Since 1996, the Potomac has been the 'sister river' of the Ara River of Tokyo, Japan | |
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 right descending bank. 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.