Data collected during a reconnaissance investigation of the geology and hydrology of sandstone aquifers provide useful information in the study of, and planning for, water-resources development in a 17,400 square-mile area in 26 counties of southwestern Kansas. The aquifers consist chiefly of saturated sandstones that occur in Upper Permian, Upper Jurassic, and Lower and Upper Cretaceous rocks. In parts of southwestern Kansas, the sandstone aquifers already serve as the principal or secondary source of ground water for irrigation and other uses. Data indicate that water may be available for development in sandstone aquifers in other parts of the study area. In still other areas, water from wells in sandstone aquifers may not be of a suitable quality for some purposes. The data provided include records of selected wells, lithologic logs of test holes and wells, selected formation surfaces and sandstone thicknesses , chemical analyses of water from selected wells, and water levels in observation wells. (USGS)