a town and river-port of England, in the North Riding of Yorkshire, on the River Tees, not far from its mouth, and about 3 miles E.N.E. of Stockton, with which it is connected by railway. Little more than twenty years ago the site of Middlesborough was occupied by a solitary farm-house. It is now the most considerable port on the Tees, though still reckoned as subordinate to Stockton. It owes its rise chiefly to its convenient situation as a port for the shipment of coals. There are commodious docks, ship-building yards, foundries, rope-walks, sail-cloth manufactories, ironworks, &c. The church of St Hilda, erected in 1840, is an elegant Gothic structure surmounted by a spire. There is also a national school, observatory, reading-room, mechanics' institute, and savings-bank. Pop. (1851) 7431.