Four types of bedrock aquifers in 12 water-management basins identified by the Indiana Natural Resources Commission (INRC) in Indiana were identified by the USGS in U.S. Geological Survey Water-Resources Investigations Report 92-4142 (Fenelon and others, 1994). The source scale of the maps depicting aquifers was 1:500,000. Aquifer maps are based on information from hydrogeologic sections and from previous studies. Attributes were compiled from tabular information contained in Fenelon and others (1994). Information contained in the report was used to identify mapped rock units within aquifer systems and distribute the aquifer characteristics to those polygons.