2714 Acres, (7 mi/11.3 km long, c.1 mi/1.6 km wide). Long Pond, located in the western sector of Mount Desert Island, is sometimes referred to as “Great” Long Pond. This helps distinguish it from the much smaller Long Pond located in Seal Harbor. Much of Great Long Pond's shores are on Acadia National Park land. It has a maximum water depth of 113 feet. Boats and fishing are allowed although, a fishing license is required for Maine residents 16 years or older and for nonresidents 12 years or older.