Water and sediment samples were collected by the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency at or near baseflow conditions from 2015-2017 in the East Fork South Fork Salmon River watershed near Yellow Pine, Valley County, Idaho. Soil, rock and tailings samples were collected in June 2015. Sampling focused on Cinnabar Creek, which flows through the Cinnabar mine site, and Sugar Creek, with additional sites selected to place the data into a larger watershed context. Grab samples were taken of the snowpack in January 2017. The water, soil, sediment, and rock samples were as described and the results are presented as separate water and solid data sets.