Dorchester Bay is the smallest of the three smaller bays of southern Boston Harbor, part of Massachusetts Bay and forming the south shoreline of the South Boston neighborhood and northeast shoreline of the Dorchester neighborhood of Boston, as well as the north shore of the city of Quincy in Massachusetts. The waters of Dorchester Bay include Pleasure Bay, Old Harbor, Western Way, Squantum Channel, Savin Hill Cove, and Dorchester Bay Basin.