During the Revolutionary War, Fort Mifflin on the Delaware River played a crucial role in holding off the British navy from resupplying their troops after the 1777 occupation of Philadelphia. The British laid siege to the fort for six weeks. The American patriots delayed the British navy long enough for George Washington and colonial troops to get to winter quarters in Valley Forge. The fort was destroyed during the fighting, but surviving colonial soldiers were able to escape, leaving the fort's flag flying.
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