Battle of Barren Hill The Battle of Barren Hill was a minor engagement during the American Revolution . On May 20 , 1778 , a British force attempted to encircle a smaller Continental force under the Marquis de Lafayette . The maneuver failed , with the Continentals escaping the trap , but the British took the field . Prelude . General George Washington sent Lafayette to reconnoiter the British forces , that occupied Philadelphia , and to determine whether they intended to attack him at Valley Forge , or move on to New York . On May 18 , Lafayette left the Valley Forge camp . After crossing the Schuylkill River and turning south , he took up position at Barren Hill , which was close to Matson ' s Ford . This area was the midway point between the British and American armies . It was here that the Americans made camp . A brigade and the guns were posted on the high ground , near a church , facing south . Another posting was at the Ridge Road to the south , and the Pennsylvania militia was sent to guard the road that led west from White Marsh . The British had discovered that the American force was nearby and decided to attack and destroy it . On May 19 , around 10 : 30 p . m . , Maj . Gen . James Grant and a 5 , 000 - man British force , including 15 guns , was sent toward Barren Hill . The plan was to take a circuitous route leading to the junction of White Marsh Road and Ridge Road . This would cut off any avenue of retreat for the Americans . A body of 2 , 000 grenadiers and dragoons would then move along Lafayette ' s left flank while another group would move into position on the American right . The plan would result in the American position being encircled from 3 positions , trapping them against the river . The British force was to wait until morning to attack and destroy or capture the entire American force . Battle . On May 20 , the British launched their attack . The militia scattered at the sight of the British troops , not offering any resistance and failing to notify Lafayette of the attack . On Ridge Road , the American group learned of the British attack . A small group was sent to fight a delaying action against the British while their commander sent word to Lafayette about the developments . After Lafayette learned of the attack , another patriot came up and told him that the British had advanced up the White Marsh Road . Lafayette knew of another small road that led back to Matson ' s Ford that would bypass the British force . It ran along some low ground that would conceal the Americans from the British . The British did not know about this road . Lafayette ordered his men to retreat down this road while ordering a rear guard to delay the British at the church . A few small patrols were sent to engage the British , skirmishing including the Oneida , making them think that the American force intended to stay and fight . Lafayette calmed his retreating force and slipped away with relatively few casualties . Aftermath . The British , having failed to bag Lafayette , resumed their retreat from Philadelphia to New York . Washington ' s army shadowed Clinton on his withdrawal and forced a battle at Monmouth on June 28 , 1778 , the last major battle in the North . Historians have questioned the decision of Washington for dispatching a sizable force under the command of such a young general in the vicinity of the British Army . Notes . See report of Gen Lafayette ' s action at Barren Hill in the Washington Papers Gen Washington at Valley Forge , May 29 , 1778 To GOUVERNEUR MORRIS