The term Greenpoint actually referred to a bluff on Freeman Street that jutted out into the East River. Eventually, the entire neighborhood acquired the name. Around the time of the Revolutionary War, Greenpoint's population consisted of just five families. Then, in 1850, ferry service to Manhattan was established, turning the neighborhood into a prominent shipbuilding industry. In fact, Greenpoint served as the construction site of the U.S.S. Monitor, the Union Navy's first iron-hulled warship in the Civil War. The thriving industry brought many Irish and, later, Polish immigrants to the area.