On this day in 1777, a British Royal Navy fleet of ships, trying to open up supply lines along the Delaware River and the occupying British army in Philadelphia, is bombarded by American cannon fire and artillery from Fort Mifflin, Pennsylvania.
Six British ships were severely damaged, including the 64-gun battleship HMS Augusta and the 20-gun sloop Merlin, which both suffered direct hits before they were run aground and subsequently destroyed. More than 60 British troops aboard the Augusta were killed, while the crewmembers aboard the Merlin abandoned ship, narrowly avoiding a similar fate.
Although the American forces defending Fort Mifflin were undoubtedly victorious on October 23, 1777, the battle continued throughout the month of October and into November. With much of the fort destroyed and under continuous artillery and cannon fire, the American forces abandoned Fort Mifflin on November 16, 1777.
The capture of Fort Mifflin gave the British Royal Navy near complete control of the Delaware River up to Red Bank, New Jersey. Fearing that the fall of Fort Mercer, located across the Delaware from Fort Mifflin, was imminent, Continental Army Colonel Christopher Greene ordered a full retreat off all Patriot troops from the fort and the burning of all buildings and ships to prevent their capture by the British. General Charles Cornwallis took over the evacuated fort, guaranteeing a safe winter for the British forces occupying Philadelphia, while their disheartened Continental counterparts froze at Valley Forge.