There are several market towns in the county. Newark-on-Trent is a bridging point of the Fosse Way and River Trent, but is actually an Anglo-Saxon market town with a now ruined castle. Mansfield, the second-largest settlement in the county after Nottingham, sits on the site of a Roman settlement, but grew after the Norman Conquest. Worksop, in the north of the county, is also an Anglo-Saxon market town which grew rapidly in the industrial revolution, with the arrival of canals and railways and the discovery of coal. Other market towns include Arnold, Bingham, Hucknall, Kirkby-in-Ashfield, Retford and Sutton-in-Ashfield.