Battle of Brandywine

The Battle of Brandywine occured on September 11, 1777 and was in Chadds Ford, Pennsylvania. September 11 began with a heavy fog, which provided cover for the British troops. Washington received contradictory reports about the British troop movements and continued to believe that the main force was moving to attack at Chadds Ford. The British appeared on the Americans' right flank at around 2 p.m. With Hazen's brigades outflanked, Sullivan, Stephen, and Stirling tried to reposition their troops to meet the unexpected British threat to their right flank. But Howe was slow to attack the American troops, which bought time for the Americans to position some of their men on high ground at Birmingham Meeting House, about a mile (2 km) north of Chadds Ford. By 4 p.m., the British attacked, with Stephen's and Stirling's divisions receiving the brunt of the assault, and both lost ground fast. Sullivan attacked a group of Hessian troops trying to outflank Stirling's men near Meeting House Hill and bought some time for most of Stirling's men to withdraw. But returned British fire forced Sullivan's men to retreat.
At this point, Washington and Greene arrived with reinforcements to try to hold off the British, who now occupied Meeting House Hill. The remnants of Sullivan's, Stephen's, and Stirling's divisions stopped the pursuing British for nearly an hour but were eventually forced to retreat. The Americans were also forced to leave behind most of their cannon on Meeting House Hill because most of the artillery horses were killed.
Knyphausen, on the east bank of the Brandywine, launched an attack against the weakened American center across Chadds Ford, breaking through Maxwell's and Wayne's divisions and forcing them to retreat and leave behind most of their cannon. Armstrong's militia, never engaged in the fighting, also decided to retreat from its positions. Further north, Greene sent Colonel Weedon's troops to cover the road just outside the town of Dilworth to hold off the British long enough for the rest of the Continental Army to retreat. Darkness brought the British pursuit to a standstill, which then left Weedon's force to retreat. The defeated Americans were forced to retreat to Chester where most of them arrived at midnight, with some stragglers arriving until morning.
The official British casualty list detailed 587 casualties: 93 killed (8 officers, 7 sergeants and 78 rank and file); 488 wounded (49 officers, 40 sergeants, 4 drummers and 395 rank and file); and 6 rank and file missing unaccounted for.[2] Only 40 of the British Army’s casualties were Hessians[3] Historian Thomas J. McGuire writes that, “American estimates of British losses run as high as 2,000, based on distant observation and sketchy, unreliable reports”.[2]
No casualty return for the American army at Brandywine survives and no figures, official or otherwise, were ever released. Most accounts of the Patriot loss were from the British side. One initial report by a British officer recorded American casualties at over 200 killed, around 750 wounded, and 400 unwounded prisoners taken. A member of General Howe’s staff claimed that 400 rebels were buried on the field by the victors.[4] Another British officer wrote that, “The Enemy had 502 dead in the field”.[2] General Howe’s report to the British Secretary of War, Lord Germain, said that the Americans, “had about 300 men killed, 600 wounded, and near 400 made prisoners”.[2]
The nearest thing to a hard figure from the Patriot side was by Major-General Nathanael Greene, who estimated that Washington’s army had lost between 1,200 and 1,300 men.[5]
350 wounded Americans were taken on September 14 from the British camp at Dilworth to a newly-established hospital at Wilmington.[6] This would suggest that of the “near 400” prisoners reported by Howe, only about 40 had surrendered unwounded.
If General Greene’s estimate of the total American loss was accurate, then between 1,160 and 1,260 Americans were killed or wounded in the battle. The British also captured 11 out of 14 of the American artillery guns.

I found this work on http://en.wikipedia.org/wiki/Battle_of_brandywine