The White, Great, and Little Miami River (WHMI) Basins in Indiana and Ohio comprise one of more than 50 study units that are part of the USGS National Water Quality Assessment (NAWQA) Program. The long-term goals of the NAWQA program are to describe the water-quality status and trends in a large representative part of the Nation's surface-water and groundwater resources and to provide a sound, scientific understanding of the primary factors affecting the quality of these resources. The WHMI NAWQA groundwater study includes the collection of groundwater-quality samples and measurement of groundwater levels in three well networks in the Glacial Aquifer System.