Newburyport is a small, coastal city in Essex County, Massachusetts, United States, northeast of Boston. The population was 17,416 at the 2010 census. A historic seaport with a vibrant tourism industry, Newburyport includes part of Plum Island. The mooring, winter storage and maintenance of recreational boats, motor and sail, still contribute a large part of the city's income. A Coast Guard station oversees boating activity, especially in the swift tidal currents of the Merrimack River.