town and metropolitan borough, metropolitan county of South Yorkshire, historic county of Yorkshire, north-central England, at the confluence of the Rivers Don and Rother just north of Sheffield. Rotherham town expanded rapidly after the founding of ironworks there in 1746, and in the 19th century it became part of a continuous industrial belt extending along the Don valley from Sheffield to Mexborough. Steelworks and engineering remain important to the local economy, but light manufactures, research and development, and service activities provide some diversification. Besides the town of Rotherham, the metropolitan borough includes suburban areas, rural villages, areas of open countryside, and the coal-mining town of Maltby. Area 119 square miles (308 square km). Pop. (2001) town, 117,262; (2006 est.) borough, 253,300.