Youngstown, city (1990 pop. 95,732), seat of Mahoning co., NE Ohio, near the Pa. line; founded 1797, inc. 1849. It was formerly a major U.S. iron and steel center. In the 1970s many of the steel mills closed, and the population of the city fell significantly. Some steel products are still produced; other manufactures include plastic and aluminum goods, electric lamps, light machinery, and household items. Aluminum extrusion and allied industries provide major employment. Discovery of iron ore, coal, and limestone led to the construction of the first iron furnace in 1803. The city's growth was spurred by the opening of the Pennsylvania and Ohio Canal (1839), the arrival of the railroad (1853), and the establishment of steel plants in the 1890s. The city is the seat of Youngstown State Univ. and the Butler Institute of American Art.