Cushing Island, or Cushing's Island, is a privately owned island in Casco Bay in the U.S. state of Maine. Part of the city of Portland, roughly 45 families live there seasonally. In 1623-24 English explorer Christopher Levett built a blockhouse on the island, part of 6,000 acres granted him by the English King. Levett left behind a group of settlers to carry on afte…Cushing Island, or Cushing's Island, is a privately owned island in Casco Bay in the U.S. state of Maine. Part of the city of Portland, roughly 45 families live there seasonally. In 1623-24 English explorer Christopher Levett built a blockhouse on the island, part of 6,000 acres granted him by the English King. Levett left behind a group of settlers to carry on after he returned to England. But the naval captain and adventurer never returned, and the fate of the men is unknown. After Levett's occupation the island was known as Andrews Island. Levett's early settlement earned him the sobriquet "the pioneer colonist in Casco Bay" from eminent Maine historian James Phinney Baxter.