Thwaite Mills or Thwaite Watermill is an industrial heritage site in Leeds, West Yorkshire, England, on the River Aire and the Aire and Calder Navigation. It is a fully restored working water-powered mill built in 1823-25, harnessing the power of the river, and has been called "one of the best last remaining examples of a water-powered mill in Britain".[1] The mill, the manager's house and three associated buildings are all grade II listed buildings. The site was open to the public as a museum operated by Leeds City Council until 1 April 2024.