This report is the first in a seies of 11 map sets depicting geohydrologic conditions in selected aquifers in upstate New York. Geohydrologic data are compiled on seven maps at 1:24,000 scale. Together, the maps provide the first comprehensive treatment of the principal aquifer in western Cortland County. The set depicts surficial geology, geologic sections, soil permeability, water-table altitude, aqufier thickness, estimated well yield, and land use. The maps are designed to help planners evaluate underground waste-disposal practices. (USGS)