Frenchman Bay (often spelled Frenchmans Bay) is a bay in Hancock County, Maine, named for Samuel de Champlain, the French explorer who visited the area in 1604. In a 1960 book titled, "The Story of Mount Desert Island", Samuel Eliot Morison wrote, "Frenchmans Bay was so called because it became a staging point for French warships preparing to fight the English."
The Frenchman Bay is bounded on the east by the Schoodic Peninsula, and on the west by Mount Desert Island; parts of both are in Acadia National Park. It contains numerous islands, the largest of which is Ironbound Island. The largest town on the bay is Bar Harbor, on Mount Desert Island. The bay extends for roughly 15 miles (24 km) and spans 7 miles (11 km) at its widest.