This data release provides Geologic Map Schema (GeMS)-compliant GIS data for new geologic mapping of the Bison Range and surrounding area on the Flathead Reservation, northwestern Montana. The database represents the geology for the 150 square kilometer, geologically complex map area, at a publication scale of 1:24,000. The map covers parts of Sanders and Lake Counties, Montana. All bedrock units exposed in the map area are metasedimentary rocks of the Mesoproterozoic Belt Supergroup that we mapped using a combination of field work and structural contouring. Surficial map units include Holocene alluvial and colluvial deposits, and Pleistocene glacial deposits. Previous mapping of surficial deposits (Ostenaa, 1990) was refined using high-resolution lidar from the U.S. Geological Survey 3D Elevation Program. The digital data present the attribute tables and geospatial features (points, lines, and polygons) in the format that meets GeMS requirements. Ostenaa, D.A., 1990, Flathead Reservation regional seismotectonic study: an evaluation for dam safety: U.S. Bureau of Reclamation Seismotectonic Report 1990-8.