This data release for the reconnaissance geologic map of the Hells Canyon Study Area, Wallowa County, Oregon, and Idaho and Adams Counties, Idaho, is a Geologic Map Schema (GeMS, 2020)-compliant version of the geologic map published in U.S. Geological Survey (USGS) Scientific Investigations Report Map SIR 2007-5046 (Simmons, et al, 2007). The database represents the geology for the 625,177-acre (2,530 square kilometers), geologically complex Hells Canyon Study Area in two plates, at a publication scale of 1:48,000. The study area includes (1) the Hells Canyon Wilderness; (2) parts of the Snake River, Rapid River, and West Fork Rapid River Wild and Scenic Rivers; (3) lands included in the second Roadless Area Review and Evaluation (RARE II); and (4) part of the Hells Canyon National Recreation Area. References: Simmons, G.C., Gualtieri, J.L., Close, T.J., Federspiel, F.E., and Leszcykowski, A.M., 2007, Mineral resources of the Hells Canyon study area, Wallowa County, Oregon, and Idaho and Adams Counties, Idaho, with a section on aeromagnetic and gravity surveys, by D.R. Mabey: U.S. Geological Survey Scientific Investigations Report 2007-5046, 62 p., https://pubs.usgs.gov/sir/2007/5046/. U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020, GeMS (Geologic Map Schema) - A standard format for the digital publication of geologic maps: U.S. Geological Survey Techniques and Methods, book 11, chap. B10, 74 p., https://doi.org//10.3133/tm11B10.