The Battle of the Chesapeake, also known as the Battle of the Virginia Capes or simply the Battle of the Capes, is a crucial naval battle in the American Revolutionary War that takes place near the mouth of Chesapeake Bay on September 5, 1781.

The combatants are a British fleet led by Rear Admiral Sir Thomas Graves and a French fleet led by Rear Admiral Francois Joseph Paul, the Comte de Grasse.

The battle is strategically decisive, in that it prevents the Royal Navy from reinforcing or evacuating the forces of Lieutenant General Lord Cornwallis at Yorktown, Virginia.

The French are able to achieve control of the sea lanes against the British, allowing them to provide the Franco-American army with siege artillery and French reinforcements—all of which prove decisive in the Siege of Yorktown, effectively securing independence for the Thirteen Colonies.

Admiral de Grasse has the option to attack British forces in either New York or Virginia; he opts for Virginia, arriving at the Chesapeake at the end of August.

Admiral Graves learns that de Grasse had sailed from the West Indies for North America and that French Admiral de Barras had also sailed from Newport, Rhode Island, and he concludes that they are going to join forces at the Chesapeake.

He sails south from New York with nineteen ships of the line and arrives at the mouth of the Chesapeake early on September 5 to see de Grasse's fleet at anchor in the bay.

De Grasse hastily prepares most of his fleet for battle—twenty-four ships of the line—and sails out to meet him, and the two-hour engagement takes place after hours of maneuvering.

The lines of the two fleets do not completely meet; only the forward and center sections fully engage

The battle is consequently fairly evenly matched, although the British suffer more casualties and ship damage, and it breaks off when the sun set.

The British tactics have been a subject of debate ever since.

The two fleets sail within view of each other for several days, but de Grasse prefers to lure the British away from the bay where de Barras is expected to arrive carrying vital siege equipment.

He breaks away from the British on September13  and returns to the Chesapeake, where de Barras had since arrived.

Graves returns to New York to organize a larger relief effort; this does not sail until 19 October, two days after Cornwallis surrenders.