Water levels for the Upper Floridan aquifer were measured throughout Florida and in parts of Georgia, South Carolina, and Alabama in May-June 2010. These measurements were compiled for the U.S. Geological Survey (USGS) Floridan Aquifer System Groundwater Availability Study and conducted as part of the USGS Groundwater Resources Program. Data were collected by personnel from the USGS Florida Water Science Center, Georgia Water Science Center, South Carolina Water Science Center and several state and county agencies in Florida, Georgia, South Carolina, and Alabama using standard techniques. Data collected by USGS personnel are stored in the USGS National Water Information System (NWIS), Groundwater Site-Inventory System (GWSI). Furnished records from cooperators are stored in NWIS/GWSI when possible, but are available from the source agency.