South Fork Musselshell River
Template:Short description Template:Use American English Template:Coord The South Fork Musselshell River is a tributary of the Musselshell River in south central Montana in the United States. It is approximately 32 miles long.<ref name="fwp">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
It rises in the Lewis and Clark National Forest in the Crazy Mountains in southern Meagher County. It flows northeast, joining the North Fork to form the Musselshell near Martinsdale just west of county line with Wheatland County.
There are five native fish found in the river: Longnose dace, Longnose Sucker, Mottled sculpin, Mountain Whitefish, and White Sucker.<ref name="fwp" /> Three varieties of trout are introduced species.<ref name="fwp" />