Workington is an ancient market and industrial town at the mouth of the River Derwent. Some parts of the town north of the River Derwent date back to Roman times. It was in the 18th century, with the exploitation of the local iron ore and coal pits, that Workington expanded to become a major industrial town and port. Iron and steel manufacture have always been part of Workington's heritage, and it was here that the famous Henry Bessemer first introduced his revolutionary steel making process. In recent years, with the decline of the steel industry and coal mining, the town has diversified into other forms of industry. The population of Workington is approximately 26,600.