Which 1781 French naval victory blocked British relief for Cornwallis during the Siege of Yorktown?

The Battle of the Chesapeake blocked British relief for Cornwallis during the Siege of Yorktown.

Also called the Battle of the Virginia Capes or the Battle of the Capes, the naval engagement took place on September 5, 1781, near the mouth of Chesapeake Bay. A French fleet commanded by the Comte de Grasse fought a British fleet led by Rear Admiral Thomas Graves.

The French fleet won a strategically decisive victory. Although neither side lost a ship in the battle, the British failed to gain control of the bay and withdrew. That prevented the Royal Navy from reinforcing or evacuating Cornwallis’s army at Yorktown.

French control of the sea lanes allowed allied troops and siege supplies to remain concentrated around Yorktown. The resulting British surrender on October 19 helped persuade Britain to negotiate an end to the war. The battle is therefore remembered as a crucial naval contribution to American independence, not merely as a separate fleet action.