The U.S. Geological Survey commenced a mineral-resource assessment of the West Pioneer Mountains, Montana in 1970. The study consists of coordinated geological, geochemical, and geophysical studies with the objective of evaluating the potential for mineral deposits in the area. The geochemical survey consists of the collection of bulk stream sediments which are analyzed for 31 elements using wet chemical and semiquantitative emission spectrographic techniques. The purpose of this report is to present the chemical analyses of the stream sediments collected to date.