The coastline of Maine in the northeastern United States is deeply indented with bays, inlets and rivers. It is generally rocky with many islands just of the shore. The largest is Mount Desert Island, with its Acadia National Park. The island is dominated by Cadillac Mountain (466 meters /1,530 feet), the highest mountain on the Atlantic coast north of Brazil.

West Quoddy Head Light marks the easternmost point of land in the United States and guides ships through the Quoddy Narrows, between the USA and Canada.