The geologic map of the Bloomington and Brodtville quadrangles includes 1:24,000 scale mapping of both surficial and bedrock geology. There is little structural folding or faulting in this portion of the Driftless Area. Thus, it is ideal for studying the hydrostratigraphic framework of the mapped units. The accompanying report presents stratigraphic observations, including estimates of secondary porosity and observations of spring distribution, that provide useful baseline data for groundwater contamination studies in the area. The supplemental GIS data include map unit polygons, field data, well construction report locations, and rasters of geologic contacts.