Every 5 years since 1950, the U.S. Geological Survey (USGS) has compiled estimates of water use for each State in the Nation and Puerto Rico. This series of compilations is used to develop and evaluate trends in water use and plan for more effective uses of the Nation's water resources in the future. This report presents water-withdrawal data, aggregated by county and water-use category, for the State of Illinois for 1995; these data were assembled for the 5-year national compilation effort by the USGS.

Definition of terms is critical in understanding water-use data. Water-withdrawal data are documented or estimated quantities of water withdrawn from surface-water or ground-water sources for public supply, commercial establishments, industrial and mining activities, irrigation and stock watering, or thermoelectric-power generation, for example. The amount of water withdrawn and the amount used in a county may not be equal because of public-supply deliveries; in Illinois, water withdrawn from a particular source is sometimes transported many miles and across county lines before being provided to the user.