MOUNT DESERT ISLAND Acadia NP Topo Lines Map: PRINTMOUNT DESERT ISLAND, Acadia National Park, MAINE. The highest peak and largest island on the U. S. East Coast, Mount Desert Island combines the quintessential textures of Maine. Rocky cliffs, ocean waves, islands, ponds, conifers and all kinds of biodiversity are accessible to the public through trails and carriage roads, mostly within Acadia National Park. The preservation of this special place is a legacy of early 19th century philanthropists and a