The Rappahannock River is a river in eastern Virginia, in the United States. It is about 195 miles (314 km) in length. It crosses the entire northern part of the state, from the Blue Ridge Mountains in the west, across the Piedmont, to the Chesapeake Bay, south of the Potomac River. The river drains an area of 2,848 square miles (7,380 km2) which is about 6% of Virginia. Much of the watershed is rural and forested. But it has experienced increased development in recent decades because it is so close to the Washington, D.C. suburbs.
It was an important river in American history. The Rappahannock was the site of early settlements in the Virginia Colony. Later, it was at the center of Eastern Theater of the American Civil War. It was a significant obstacle to north-south movements via land. As a result it functioned as the war's eastern-theatre boundary, between the "North" (the Union) and the "South" (the Confederate States of America).