The Chesapeake Bay was the site of the Battle of the Chesapeake (also known as the "Battle of the Capes", Cape Charles and Cape Henry) in 1781, during which the French fleet defeated the Royal Navy in the decisive naval battle of the American Revolutionary War. The British defeat enabled General George Washington and his French allied armies under Comte de Rochambeau to march down from New York and bottle up the rampaging southern British Army of Lord Cornwallis from the North and South Carolinas at the siege of Battle of Yorktown in Yorktown, Virginia. Their marching route from Newport, Rhode Island through Connecticut, New York State, Pennsylvania, New Jersey and Delaware to the "Head of Elk" by the Susquehanna River along the shores and also partially sailing down the Bay to Virginia. It is also the subject of a designated National Historic Trail as the Washington–Rochambeau Revolutionary Route.
The Bay would again see conflict during War of 1812. During the year of 1813, from their base on Tangier Island, British naval forces under the command of Admiral George Cockburn raided several towns on the shores of the Chesapeake, treating the Bay as if it were a "British Lake". The Chesapeake Bay Flotilla, a fleet of shallow-draft armed barges under the command of U.S. Navy Commodore Joshua Barney, was assembled to stall British shore raids and attacks. After months of harassment by Barney, the British landed on the west side of the Patuxent at Benedict, Maryland, the Chesapeake Flotilla was scuttled, and the British trekked overland to rout the U.S. Army at Bladensburg and burn the U.S. Capitol in August 1814. A few days later in a "pincer attack", they also sailed up the Potomac River to attack Fort Washington below the National Capital and raided the nearby port town of Alexandria, Virginia.
There were so-called "Oyster Wars" in the late 19th and early 20th centuries. Until the mid-20th century, oyster harvesting rivaled the crab industry among Chesapeake watermen, a dwindling breed whose skipjacks and other workboats were supplanted by recreational craft in the latter part of the century.
In the 1960s, the Calvert Cliffs Nuclear Power Plant on the historic Calvert Cliffs in Calvert County on the Western Shore of Maryland began using water from the Bay to cool its reactor.