port town and borough (district), administrative county of Cumbria, historic county of Lancashire, England. It lies on the seaward side of the Furness peninsula between the estuary of the River Duddon and Morecambe Bay. A narrow channel of the Irish Sea, now bridged, lies between the mainland and the low, elongated Isle of Walney, providing shelter for extensive shipyards. The rapid modern growth of Barrow dates from the 1840s, when ironworks were established using local high-grade ore and coke brought by rail across the Pennines. Shipbuilding and repairing—for Royal Navy and merchant vessels—later developed and outstripped the steel industry in economic importance; the local ore supply is now almost exhausted. Submarines have become a noted product of the shipyards, and the borough is a centre of nuclear engineering. Area borough, 30 square miles (77 square km). Pop. (2001) town, 47,194; borough, 71,979.