The event often cited as the decisive factor leading to the British surrender at Yorktown is The French blockade.

The French fleet effectively blocked British reinforcements and supplies from reaching General Cornwallis’s troops, trapping them at Yorktown. This naval blockade severely limited Cornwallis’s ability to sustain his forces and ultimately forced him to surrender on October 19, 1781. The combination of the blockade and the coordinated assault by American and French troops underscored the critical role that international alliances played in achieving a decisive victory in the American Revolutionary War.