Short answers, pulled from the story.
The Potomac River is 405 miles long. It flows from the Potomac Highlands in West Virginia to Chesapeake Bay in Maryland, draining a watershed of 14,700 square miles and passing through the nation's capital, Washington, D.C.
The Potomac earned the nickname because of its deep ties to American political history. Washington, D.C. was placed on its banks by act of Congress in 1790, George Washington was born and spent most of his life within the basin, and the Union's largest Civil War army, the Army of the Potomac, took its name from the river.
Maryland holds ownership of the river bank-to-bank from the low-water mark on the Virginia side, under the terms of the 1785 Mount Vernon Compact and the 1877 Black-Jenkins Award. Virginia retains full riparian rights to use the river as long as it does not obstruct navigation. The Supreme Court reaffirmed this arrangement in a 7-2 decision on the 9th of December, 2003.
The Potomac was declared a national disgrace by President Lyndon Johnson in the 1960s due to severe algal blooms from sewage and agricultural runoff. Recovery efforts including the 1972 Clean Water Act and phosphorus controls in the 1980s reversed much of the damage. The Potomac Conservancy has issued the river a grade of B since 2018, though a sewage pipe rupture on the 19th of January, 2026, spilled 300 million gallons into the river at contamination levels thousands of times above safe thresholds.
Potomac is a European spelling of Patawomeck, the Algonquian name of a Native American village on the river's southern bank, recorded by Captain John Smith during his 1608 exploration. The Board on Geographic Names officially settled on the spelling Potomac in 1931.
The Potomac served as the boundary between the Union and the Confederacy. General Robert E. Lee crossed it twice to invade the North, leading to the Battle of Antietam on the 17th of September, 1862, and the Battle of Gettysburg from the 1st to the 3rd of July, 1863. Confederate General Jubal Early crossed the river in July 1864 in an attempted raid on Washington, D.C.