Frays River is a semi-canalised short river in England that branches off the River Colne at Uxbridge Moor and rejoins it at West Drayton. The river is believed to be a man-made diversion of waters from the River Colne to feed watermills around Uxbridge. The name is originates from John Fray who owned Cowley Hall beside the river in the fifteenth century. Other names for the river are the Uxbridge and Cowley Mill Stream, the Cowley Stream or the Colham Mill Stream. In the 17th century the river powered five mills. Drayton Mill at West Drayton was mentioned in Domesday Book and was used for flour milling, paper-making and the manufacture of millboard. It ceased operation in about 1923.