This report presents data on hydrogeology and water quality at the Upper Sioux Indian Community, located along the Minnesota River in southwestern Minnesota. Data were collected during 1994-96 by the U.S. Geological Survey in cooperation with the Upper Sioux Indian Community. The data will serve as a reference to monitor potential changes in hydrogeologic and water-quality conditions at the Community. The data include: (1) river stage in Hazel Creek; (2) a geologic log at a test hole near the Community; (3) texture analysis of selected samples from auger cuttings at the test hole; (4) specific conductance, pH, temperature, dissolved oxygen, and hardness measurements in water samples collected from 16 ground-water sites and 5 surface-water sites; (5) cation, anion, and trace-metal concentrations in water samples from 16 ground-water sites and 5 surface-water sites; (6) fecal coliform and fecal streptococcal bacteria colony counts in water samples from 9 ground-water sites; (7) nutrient concentrations in water samples from 16 ground-water sites and 5 surface-water sites; and (8) pesticide concentrations in water samples from 6 ground-water sites,
