This report presents data on precipitation, geologic logs, water levels, and water quality that have been collected or compiled, through water year 1993, for the Huron Project of the High Plains Ground-Water Demonstration Program, under the guidance of the Bureau of Reclamation. The purpose of the Huron Project is to demonstrate the artificial recharge potential of glacial aquifers in eastern South Dakota. High flows from the James River during spring runoff are used as a source of supplemental recharge for the Warren aquifer, which is a buried, glacial aquifer. Prior to the injection of recharge water, which began in April 1994, many sites were monitored to obtain background information. This report presents data that were collected prior to the initiation of recharge. Precipitation data are collected at two sites within the study area. A site description and daily precipitation for water years 1991-93 are presented for one precipitation site. In 1990, 76 test holes were drilled and observation wells were installed at 70 sites. Well information and geologic logs collected during the drilling program for the Huron Project are presented. In addition to the 70 new Huron Project wells, 15 existing observation wells owned by the South Dakota Department of Environment and Natural Resources were incorporated into the study. Water- level hydrographs are presented for the 85 observation wells. The period of record shown for the hydrographs is from the earliest available record through September 1993. Water-quality data were collected from both screening and detailed sampling programs. Screening water-quality data for 32 observation wells are presented. These data include primarily field parameters and common ions. The eight detailed sampling sites represent the quality of untreated water, treated water, an intermittent stream, and ground water from the Warren aquifer. Data presented for the detailed sampling program include field parameters, bacteria counts, and concentrations of common ions, solids, nutrients, trace elements, radiometrics, total organic carbon, herbicides, insecticides, and volatile organic compounds.