Sears Island, known as Wassumkeag or shining beach by the indigenous Wabanaki tribes of northern New England, is located off the coast of Searsport in Waldo County, Maine at the top of Penobscot Bay.The island is the largest undeveloped, uninhabited, causeway-accessible island on the eastern coast of the United States. It is 940 acres (3.8 km2) in area. It is part of the Town of Searsport.