Losing his grip on the Carolinas, Cornwallis marched his army into Virginia and seized Yorktown and Gloucester, towns on each side of the York River.
With the arrival of the French fleet of Admiral De Grasse, General Washington was able to march south from New York with the joint American and French army to attack Cornwallis.
The Americans and French marched out of Williamsburg and arrived before Yorktown on 28th September 1781, forming a semi-circle around the entrenchments and putting the British under siege. Cornwallis expecting Major General Clinton to sail from New York with a relieving force had decided to remain in Yorktown rather than march south to the Carolinas or attempt to reach New York. His first move was the inexplicable one of abandoning a line of four redoubts that dominated the British positions. The Americans immediately occupied the empty redoubts.
The Americans began formal siege operations on the eastern side of Yorktown on 30th September and on 9th October were sufficiently close to began an artillery bombardment.
On 14th October the Americans and French stormed two redoubts in front of their trenches and the position of the British in Yorktown became untenable.
The British carried out a sortie on the 16th in which several guns in the two redoubts were spiked. On the same day Cornwallis attempted to pass the Guards, the 23rd and the Light Infantry across the York River to Gloucester but was thwarted by a storm.
With no sign of Clinton’s relief and with inadequate supplies of artillery ammunition and food, on 19th October 1781 Cornwallis’ army marched out of Yorktown and surrendered.