In 2015, the U.S. Geological Survey (USGS), in cooperation with the New York State Department of Environmental Conservation (NYSDEC), began an appraisal of the sand and gravel aquifers within the Owasco Inlet watershed, which covers about 117 square miles (mi2) and drains north directly to Owasco Lake, one of New York’s Finger Lakes. About three-quarters of the watershed is within Cayuga County; the remaining area (southern end) is in Tompkins County. The Owasco Inlet valley stretches about 18 miles (mi) from Owasco Lake south to the divide at Freeville. Major tributaries include Hemlock Creek on the west side of the watershed and Dresserville and Decker Creeks on the east side. A variety of data were compiled, collected, and synthesized to provide a broad picture of the glacial deposits, hydrogeologic framework, aquifer occurrence, and water-resource potential in the area. Geospatial datasets (shapefiles) of aquifer extents, wells, surficial geology and glacial features are detailed in child items associated with this data release.