Hydrogeologic data for selected test wells drilled in the Fort Union coal region, eastern Montana

Hydrologic and geologic data have been collected as part of energy-related projects conducted by the U.S. Geological Survey in 11 counties of eastern Montana. Records of 408 test wells are tabulated in this report. The data include well location, type of well, date drilled, well depth, type and diameter of casing, depth cased, interval open to well, principal aquifer, depth to water level, water-level-record dates, water-quality-sampling record, and type of logs available. Location of the wells is shown by county on maps at a scale of 1:500,000.