The city, the most populous in the state, is a port on Long Island Sound at the mouth of the Pequonnock River. Black Rock Harbor is a deep, protected harbor that developed as a trade port and shipbuilding center in the 18th century. Black Rock was once part of Fairfield, but now is a neighborhood of the city of Bridgeport. Bridgeport’s advantageous geographic location, situated around an excellent harbor on the Long Island Sound, encouraged the early settlers to shift from agrarian to mercantile and manufacturing pursuits. Today the Bridgeport & Port Jefferson Steamboat Company provides daily ferry service between Bridgeport and Port Jefferson, Long Island from their new terminal and docking facility and major transportation hub. The approxvimate population of Bridgeport is 139,529.