Fort George was central to a little-known American military disaster that is still studied today by the United States armed forces.
The fort was begun by British troops after they occupied the region in June 1779, during the American Revolution. Strategically, it was located on the highest point of ground overlooking the entrance to Penobscot Bay.
In late July of 1779, the Massachusetts legislature sent a combined military and naval force, known as the Penobscot Expedition, to expel the British and capture the fort. The Expedition included eighteen armed ships, twenty-one transports, 900 militiamen, and 300 Continental Marines. Construction on the fort had barely begun, and British troops numbered only 700. Yet the rebel force suffered a disastrous defeat due to a series of delays and poor decisions by the American commanders. The British completed construction of Fort George and maintained control of the area until 1784.
Miss Amy Witherle bequeathed the site of the Fort to the State of Maine upon her death in 1949, and it was listed on the National Register of Historic Places in 1969. More information about the Penobscot Expedition is available at the Castine Historical Society.