This is the second in a series of 11 map sets depicting hydrogeologic conditions in selected upstate aquifers in upstate New York. Geohydrologic data are compiled on seven maps at 1:24 ,000 scale. Together the maps provide a comprehensive overview of the principal aquifer in western Oswego County. The set includes surficial geology, geologic sections, soil permeability , water-table altitude, aquifer thickness, estimated well yield, and land use. The maps are designed to enable planners to evaluate waste-disposal practices that may adversely affect the aquifer. (USGS)