Cayoosh Creek flows generally northeast from sources in the eponymous Cayoosh Range north of Cayoosh Pass to join the Seton River at Lillooet, British Columbia. In local parlance, the 4 kilometre length of the Seton River to its confluence with the Fraser River at the town of Lillooet is referred to as Cayoosh Creek, as is indicated by a Department of Highways sign on the BC Highway 99 bridge crossing it just before the Bridge of the Twenty-Three Camels over the Fraser, which lies immediately upstream of the river's mouth.