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, as they were vulnerable to attack while trying to cross the river on temporary bridges. 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 General Ulysses S. Grant in the Wilderness (or Overland) Campaign of 1864, ending in the ultimate Union victory.