Squantum is a neighborhood of Quincy, Massachusetts connected to the mainland by a causeway that crosses over a wetland area of the bay. Often thought of as a peninsula, Squantum proper is technically a barrier island as it is surrounded on all four sides by water and is only connected to the mainland and Moon Island via causeways. Located in the northernmost portion of the city, Squantum is bordered on the north by Dorchester Bay and Boston Harbor, on the east by Moon Island and Quincy Bay, on the south by Quincy Bay and North Quincy and on the west by the Marina Bay development.