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. The population of the neighborhood in 2010 according to the United States Census Bureau was 2,365. Squantum has scenic, waterfront views of Boston Harbor and the Boston skyline and has many of Quincy’s most expensive homes. Squantum residents are the wealthiest of any neighborhood in Quincy, according to the 2010 United States Census Bureau, and the home ownership rate is approximately 92%. The neighborhood is further characterized by its tree-lined streets, its "island getaway" feel, close-knit community, and its annual Squantum Fourth of July Parade. As described in a 2020 book, "One road leads in and out of a square mile of land that is a playground for children and a haven for adults." Squantum also has one of the largest Irish populations, on a per capita basis, of any neighborhood in the United States.

North Quincy is a neighborhood of Quincy, Massachusetts. It is separated from the city of Boston by the Neponset River, and borders the Quincy neighborhoods of Squantum, Montclair and Wollaston. It contains the smaller neighborhoods of Atlantic and Norfolk Downs, as well as much of Wollaston Beach.