The River Stinchar has its headwaters in the Carrick Forest to the north of the Galloway Forest Park, and only one kilometre from the source of the river Girvan. It has a main drainage course of 54 kilometres and from its source initially flows north before turning south westward through Barr, Pinwherry and Colmonell to enter the sea at Ballantrae. The river has a catchment area of 253 square kilometres, which includes the main tributaries of the Muck Water, the River Duisk, the Water of Tig and the Assel.