The River Nith is a river in south-west Scotland. The Nith rises in the Carsphairn hills of East Ayrshire, between Prickeny Hill and Enoch Hill, 4.4 miles east of Dalmellington. For the majority of its 70 miles course it flows in a south-easterly direction through Dumfries and Galloway and then into the Solway Firth at Airds Point.