The U.S. Geological Survey began a Regional Aquifer- System Analysis of the Northern Rocky Mountains Intermontane Basins of western Montana and central and central and northern Idaho in 1990 to establish a regional framework of information for aquifers in 54 intermontane basins in an area of about 77,500 square miles. Selected hydrogeologic data have been used as part of this analysis to define the hydro- logic systems. Records of 1,376 wells completed in 31 of the 34 intermontane basins in the Montana part of the study area are tabulated in this report. Data consist of location, alttiude of land surface, date well constructed, geologic unit, depth of well, diameter of casing, type of finish, top of open interval, primary use of water, water level, date water level measured, discharge, specific capacity, source of discharge data, type of log available, date water-quality parameters measured, specific conductance, pH, and temperature. Hydrographs for selected wells also are included. Locations of wells and basins are shown on the accompanying plate.