Potomac River
river in the mid-Atlantic United States
The Potomac River ( ) is in the Mid-Atlantic region of the United States and 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. More than 6 million people live within its watershed.
The river forms the boundary separating the jurisdictions on its left descending bank (Maryland and Washington, D.C.) from those on its right descending bank (West Virginia and Virginia). 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. All navigable parts of the river were designated as a National Recreation Trail in 2006, and the National Oceanic and Atmospheric Administration (NOAA) designated an 18-square-mile (47 km2) portion of the river in Charles County, Maryland, as the Mallows Bay–Potomac River National Marine Sanctuary in 2019.
The river has significant historical and political significance, as the nation's capital of Washington, D.C. is located on its banks, as is Mount Vernon, the home of George Washington. During the American Civil War, the river became the boundary between the Union and the Confederacy, and the Union's largest army, the Army of the Potomac, was named after the river.
Course
The Potomac River runs 405 mi (652 km) from Fairfax Stone Historical Monument State Park in West Virginia on the Allegheny Plateau to Point Lookout, Maryland, and drains 14,679 sq mi (38,020 km2).
This brief starts where responsible research should: with the source description of “Potomac River” as river in the mid-Atlantic United States. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the places & architecture register because the source frames it as river in the mid-Atlantic United States. Its deeper value depends on whether names, dates, institutions and citations support that framing.
The strongest evidence will usually combine a dated visual record with documents produced by the authority responsible for the place. The source revision retrieved here is dated Sep 23, 2026. The linked authority identifier is Q179444. VIAF identifies the subject as 315129144. The Library of Congress control number is sh85105689. Authority coordinates are 39.528, -78.588. 4 of 4 selected statements include explicit references; 2 carry qualifiers and 0 use preferred rank. The first chronological checks are 2006 and 2019.
Architectural summaries often privilege surviving fabric and can understate demolished phases, contested use or displaced communities. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Treat names, boundaries and functions as historically changeable. Maps, plans, inventories and administrative records can clarify what the place meant at different dates.
- Historic place names
- Jurisdictional context
- Routes into maps and plans
Contemporary maps, plans, listed-building records, estate papers and the responsible local or national archive.
Three-step research path
- Establish the record: confirm the title “Potomac River”, its source revision and the description used here.
- Expand the search: follow Potomac River primary sources, Potomac River archive and Potomac research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Potomac River”?
- What physical evidence or contemporary plan supports the description?
- Which authority defined the place, boundary or structure at the relevant date?
Search terms from this dossier
This entry incorporates text from “Potomac River” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.