Hydrologic and geologic data have been collected as part of energy-related projects conducted by the U.S. Geological Survey in the northern Powder River basin of southeastern Montana. Records of 1924 stock, domestic, irrigation, public supply and test wells are tabulated in the report. The data include well location, depth of well, casing diameter, type of lift, type of power, use of water, principal aquifer, altitude of land surface , water level, discharge, field specific conductance, and water temperature. Locations of the inventoried wells are shown on a map at a scale of 1:500,000. Lighologic logs of 373 wells and test holes are also included. The geologic units considered range in age from Late Cretaceous to Holocene. (Kosco-USGS)