city of county status and seat of Nógrád megye (county), north-central Hungary. It lies in the Tarján River valley near the border with Slovakia and is surrounded by hills. Industrial development, based on extensive brown-coal deposits, began in the late 19th century. The development of the coal mines produced the most militant traditions of the Hungarian labour movement. Salgótarján has a cast iron foundry, glassworks, and factories producing household appliances, insulating materials, and electronic goods. Many of the city's narrow ancient streets have notable houses from the 17th and 18th centuries. The nearby hills of Várhegy (“Castle Hill”), Karancs, and Boszorkánykö (“Witches' Crag”) offer panoramic views. The ruined 13th-century Salgó Castle is on a basalt cone (2,050 ft 【625 m】) overlooking the city. Pop. (2001) 44,964.