A Vortex of Artillery, Mud, and Rain: Working to Preserve Fort Mifflin and its Defender’s 2-Month Duel with the Royal Navy

A drawing of the British bombardment of Fort Mifflin on November 15, 1777

Courtesy of New York Public Library

Recipient: University of Pennsylvania

Amount: $113,440.32

After the British Army’s victory at the Battle of Brandywine and capture of the American capital of Philadelphia, Pennsylvania in the late summer of 1777, their commanding officer, Sir William Howe, faced the growing problem of having outpaced an increasingly threatened supply line. With cold weather looming and provisions coming from far overland in Maryland, Howe knew he had to be resupplied more directly by the Royal Navy or his army would starve and be forced to retreat. To fix his supply issues, however, Howe had to solve another major problem.

Standing between Howe’s Army and the Royal Navy on the Delaware River were a series of American Forts, gunboats, and sunken chevaux de frise – massive boxes of stone and logs tipped with iron spikes that could pierce the underside of a warship’s hull. For two months these defenses held the British at a standstill, defeating repeated attempts by the Royal Navy to breakthrough and turning back an attack by Howe’s Infantry at Redbank.

The keystone to the American defenses was Fort Mifflin, a partially completed bastion on Mud Island that commanded both sides of the Delaware River. On November 15th, after weeks of attempting to bombard the Fort into submission, the Royal Navy attacked with a full squadron of ships and sailed HMS Vigilant and Fury to within point-blank range of the fort. The ensuing artillery barrage was the largest concentration of artillery fire during the entire war. Outgunned and facing the real threat of being surrounded, the American defenders held out until nightfall and then abandoned the Fort.

Using the financial support of a Preservation Planning Grant, the University of Pennsylvania will organize and facilitate a three-phased archeological field survey of Fort Mifflin. By conducting limited excavation, geophysical survey, and archaeobotanical data collection, the University intends to recover information vital to reassessing current site conditions, and developing a more informed, long-term preservation plan for the Fort.

Preservation Planning Grants from the National Park Service’s American Battlefield Protection Program support a variety of projects that are focused on the preservation and interpretation of sites of armed conflict, including battlefields and associated sites on American soil. In addition to this grant opportunity, the program also provides financial assistance through Battlefield Land Acquisition Grants, Battlefield Interpretation Grants, and Battlefield Restoration Grants, to help generate community-driven stewardship of historic resources at the state, tribal and local levels.