Siege of Fort Mifflin

The Siege of Fort Mifflin was one of the most sustained and costly defensive operations of the war, with the small American garrison enduring weeks of intensive British bombardment on a river island to delay British supply ships from reaching Philadelphia. If Fort Mifflin and Fort Mercer could deny the Delaware River to British shipping, Philadelphia might become untenable for the British despite its capture.

The British brought up shore batteries and floating artillery platforms, beginning a systematic bombardment. For five weeks the garrison withstood increasingly intense fire. The battered wooden fort was repeatedly repaired at night under fire. Individual acts of heroism were commonplace — soldiers manning cannon as the structures around them were demolished.

By November the bombardment had become overwhelming. Six British warships moved to point-blank range and fired over 1,000 cannon rounds in a single day. The surviving defenders evacuated under cover of darkness on November 15-16, having held for over five weeks. About 250 Americans died in the siege.

The garrison's extraordinary resistance was ultimately in vain — Philadelphia remained in British hands — but the delay forced Howe to consume time and resources on the river forts rather than pursuing Washington's army or consolidating his position. The soldiers who defended Fort Mifflin are considered among the most determined of the entire war.