Acadia National Park (ANP) reserves much of Mount Desert Island, and associated smaller islands, off the Atlantic coast. Originally created as Lafayette National Park in 1919, the first National Park East of the Mississippi, it was renamed Acadia in 1929.

The park includes mountains, an ocean shoreline, woodlands, and lakes. In addition to Mount Desert Island, the park comprises much of the Isle au Haut, parts of Baker Island, and a portion of the Schoodic Peninsula on the mainland.