This U.S. Geological Survey (USGS) data release provides an updated digital geospatial database for the geologic map of the Choteau 1 x 2 degrees quadrangle, western Montana (Mudge and others, 2001). Attribute tables and geospatial features (lines and polygons) conform to the Geologic Map Schema (USGS NCGMP, 2020) and represent the geologic map as published in USGS Miscellaneous Investigations Series Map I-1300 (Mudge and others, 1982). Minor errors, such as mistakes in line decoration or differences between the digital data and the map image, are corrected in this version. The database represents the geology for the 4.2 million acre, geologically complex Choteau 1 x 2 degrees quadrangle, at a publication scale of 1:250,000. The map covers primarily Lewis and Clark, Teton, Powell, Missoula, Lake, and Flathead Counties, but also includes minor parts of Cascade County. These GIS data supersede those in the report (Mudge and others, 2001). References: Mudge, M.R, Earhart, R.L., Whipple, J.W., Harrison, J.E., Munts, S.R., and Silkwood, J.T., 2001, Geologic and structure map of the Choteau 1 x 2 degrees quadrangle: a digital database: U.S. Geological Survey Miscellaneous Investigations Series Map I-1300, scale 1:250,000, https://pubs.usgs.gov/imap/i1300/. Mudge, M.R, Earhart, R.L., Whipple, J.W., and Harrison, 1982, Geologic and structure map of the Choteau 1 x 2 degrees quadrangle: U.S. Geological Survey Miscellaneous Investigations Series Map I-1300, scale 1:250,000, https://doi.org/10.3133/i1300. 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.