Cornwallis, promoted to Major General before he left for America in February 1776, had several early successes. In August 1776, he was part of the army that forced the Continental Army out of Long Island, Manhattan, and New Jersey. As General Howe occupied New Jersey, Cornwallis chased the Continentals for more than eighty miles. He nearly caught Washington in New Brunswick, New Jersey on the banks of the Raritan River, but received orders from Howe to go no further. Regarded as one of the great, lost opportunities of the war, Cornwallis's pursuit had the possibility of ending the conflict in its early stages. The revolution was at one of its lowest points and the Continental Army was in constant retreat. Obediently, Cornwallis waited for Howe to join him from New York. As winter approached, the season for military campaigns was ending and the respective armies were preparing winter quarters. Cornwallis, ready to go to London on leave, was waiting for his ship in New York City when word reached him that Washington had crossed the Delaware River and attacked at Trenton, New Jersey. .
Early in 1777, Cornwallis suffered humiliation at the hands of Washington. After a day's march through thick mud and random enemy fire, mostly from snipers, he caught up with Washington at Trenton. He believed the Delaware River blocked any possible escape for the Continental Army, and so rested his troops without posting a guard. Henry Clinton described his action as "the most consummate ignorance ever heard of [in] any officer above a corporal. " Washington left a small contingent with a few fires burning, and, wrapping the wheels of his gun carriages to muffle them, escaped in the night. Cornwallis dismissed this as his enemy's last, desperate gasp. Washington in turn advanced on Princeton, destroying a bridge that would have allowed Cornwallis to follow him, and attacked the rear guard of Cornwallis' army.