This U.S. Geological Survey (USGS) data release provides an updated digital geospatial database for the geologic map of the Butte 1 degree x 2 degrees quadrangle, Montana (Lewis, 1998). Attribute tables and geospatial features (points, lines and polygons) conform to the Geologic Map Schema (USGS NCGMP, 2020) and represent the geologic map as published in Montana Bureau of Mines and Geology Open File Report MBMG 363 (Lewis, 1998). 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 4.4 million acre, geologically complex Butte 1 degree x 2 degrees quadrangle, at a publication scale of 1:250,000. The map covers parts of Deer Lodge, Granite, Jefferson, Lewis and Clark, Missoula, Powell, Ravalli, and Silver Bow Counties. These GIS data supersede those in the interpretive report (Lewis, 1998). References: Lewis, R.S., 1998, Geologic map of the Butte 1 x 2 quadrangle, southwestern Montana: Montana Bureau of Mines and Geology Open-File Report 363, 16 p., 1 sheet, scale 1:250,000, http://www.mbmg.mtech.edu/mbmgcat/public/ListCitation.asp?pub_id=11212&. 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://pubs.er.usgs.gov/publication/tm11B10.