This U.S. Geological Survey (USGS) data release (ver. 1.2, April 2022) contains a set of previously unpublished geochemical data from project studies of primitive areas in central Idaho, including the Clear Creek-Upper Big Deer Creek Area, the Salmon River Breaks and Sawtooth Primitive Areas, and the Gospel-Hump Wilderness Area. The purpose of the USGS Idaho Primitive Area studies, conducted from 1966 to 1984, was to describe the geology, determine petrologic and geochemical characteristics, and evaluate the mineral resource potential of these primitive areas and adjacent study areas. In the case of the Idaho Primitive Area study (Cater and others, 1973), the primitive area covers 1,915 square miles; adjacent study areas added in 1967 included an additional 272 square miles, for a total of 2,187 square miles. The contiguous Clear Creek-Upper Big Deer Creek Area was studied separately (Cater and others, 1975) and covers 85 square miles. The Salmon River Breaks Primitive Area study (Weis and others, 1972) covers 420 square miles of primitive area and adjacent study areas. The Sawtooth Primitive Area study (Kiilsgaard and others, 1970) covers 434 square miles of primitive area and adjacent study areas. Also included in this release are previously unpublished geochemical data of 65 rock samples collected and analyzed under the Gospel-Hump Wilderness Area project. The 5,167 samples collected in these primitive areas are made up of 2,667 stream sediment samples, 1,201 rock samples, 194 soil samples, 94 bulk pan concentrate samples, and one precipitate sample. More than 99 percent of these samples were analyzed by semi-quantitative, visual 6-step emission spectrography multi-element scan. Many samples were also analyzed by flame-atomic absorption spectrophotometry for gold, silver, cobalt, copper, lead, and zinc; by colorimetry for arsenic, cobalt, copper, heavy metals, fluorine, antimony, uranium, and tungsten; by atomic absorption spectrophotometry for mercury after thermal release; and by gamma ray counting for uranium and thorium. The data for many standard reference materials that were also analyzed with these samples for quality assurance purposes are not included in this data release. Accurate site ___location information was not available for 1,329 samples from these studies. Also, 1,010 samples are referred to as geologic material samples, as more specific sample media type information was not available. These data may still be valuable to the user and are included in this data release.