The Rappahannock River rises at Chester Gap, a wind gap in the Blue Ridge Mountains a few miles southeast of Front Royal, Virginia, near the single point where Warren, Fauquier, and Rappahannock counties come together. It flows southeastward, past Remington, Kelly's Ford, and Richardsville, before it is joined by the Rapidan River, its largest tributary, from the right.
Then the Rappahannock passes through the city of Fredericksburg. Southeast of Fredericksburg, it begins to slow and widen into a brackish tidal estuary approximately 50 miles (80 km) long. It passes two small, but historic, river towns, Port Royal and Port Conway, which sit opposite each other, the former on the south bank, the latter on the north. Then it flows past Tappahannock on its southern bank, a point where the river is well over a mile wide. The last settlements of any size before reaching the Chesapeake Bay are Irvington, Urbanna, Stingray Point, and White Stone Beach.
The broad river enters the Chesapeake Bay approximately 20 miles (32 km) south of the mouth of the Potomac River and approximately 60 miles (97 km) east of the state capital, Richmond. At the point where the river enters the bay, between Windmill Point, on the north, and Stingray Point, on the south, it is more than 3.5 miles (5.6 km) wide. This area, the estuary south of the Northern Neck peninsula, is a productive oyster and crab fishery.
Although there had been a few small hamlets along the lower Rappahannock during early colonial times, the settlement of the Rappahannock River valley began in earnest during the first years of the eighteenth century, at the urging of Governor Alexander Spotswood. The James River had been surveyed up to its fall line, the point where, geologically, continental bedrock of the Piedmont meets the sedimentary rocks and alluvial soils of the coastal plain. Spotswood encouraged settlement in a river valley other than that of the James. In 1714, he began soliciting immigrants from the Rhineland-Palatinate and Switzerland to homestead on lands he controlled near the confluence of the Rappahannock and the Rapidan. Known as the Germanna settlement(s), these villages were founded in order to exploit the iron ore deposits of the region.
The Battle of Rappahannock River was fought on the river during the War of 1812. Seventeen British boats filled with hundreds of marines and sailors captured four American privateers.
During the American Civil War, the river, with few convenient fords and fewer bridges, provided a barrier and defensive line behind which movements of troops could be accomplished with little fear of attack from the river-side flank. It was an especially difficult barrier for Union troops to overcome in their attempts to thrust into southern Virginia. Control of the river changed hands many times during the course of the war. Significant battles fought along the river include the Battle of Fredericksburg and the Battle of Rappahannock Station. The defensive line at the river was finally circumvented by Ulysses S. Grant in the Wilderness (or Overland) Campaign of 1864, ending in the ultimate Union victory.