Selected hydrologic data have been used in a 4-year study of aquifers of Cenozoic and Mesozoic age in the northern Great Plains to define the hydrologic system and to generate hydrologic maps. Records of 6,754 wells and 188 springs are tabulated in the report. The well data include site location, county, date completed, depth of well, casing diameter, type of lift, use of water, principal aquifer, altitude of land surface, water level, discharge, specific capacity, specific conductance, and water temperature. The spring data include site location, county, use of water, principal aquifer, altitude of land surface, type of spring, discharge, date discharge measured, specific conductance, and water temperature. Locations of the wells and springs are shown on a map at a scale of 1:1,000,000. (USGS)