Matlock is located on the River Derwent in a fairly central position in Derbyshire. At Matlock, the Derwent carves its way through hard limestone rock, creating Matlock Dale, one of Derbyshire's most spectacular dales, with crossing points of the river at each end of the dale, at Matlock and at Cromford. Matlock Bridge lies on an ancient route formerly used for the transport of locally mined lead eastwards to Nottingham and beyond.Matlock developed rapidly following the arrival of the railway in 1849, giving it a legacy of fine nineteenth century buildings. Matlock Bath developed as a popular inland resort from the eighteenth century, set in the beautiful scenery of Matlock Dale. At the southern end of the dale, Richard Arkwright constructed Masson Mill in 1783 and this site is now the start of the Derwent Valley World Heritage Site (designated in 2001).