Fort George (also sometimes known as Fort Majabigwaduce, Castine, or Penobscot) was a palisaded earthworks fort built in 1779 by Great Britain during the American Revolutionary War in Castine, Maine. Located at a high point on the Bagaduce Peninsula, the fort was built as part of an initiative by the British to establish a new colony called New Ireland. It was the principal site of the British defense during the Massachusetts-organized Penobscot Expedition, a disastrous attempt to retake Castine launched in response to the British move.