Illinois has an abundance of groundwater resources that supply millions of gallons of water per day to public, irrigation, and commercial/industrial systems. Groundwater resources are unevenly distributed throughout Illinois due to the state’s complex bedrock and glacial geology. This interactive map depicts the three major aquifer systems in Illinois and the public water supply (PWS) wells that extract groundwater from them. Users can select or query wells based on spatial location or attribute, and then can view reported withdrawals in an attribute table or in graph view. Users can also export data found in the attribute tables as a CSV file and can output maps in various formats for printing.