From 1950 through 1995, the U.S. Geological Survey tabulated water withdrawals throughout the United States, including the northcentral States of Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, and Wisconsin. During this period, total water withdrawals increased in each of the north-central States by at least a factor of two. Illinois led the north-central States in total withdrawals, withdrawals from surface water and, typically, withdrawals from ground water. Per capita withdrawals were largest in Indiana or Illinois, however, the disparity in per capita withdrawals in the north-central States decreased from 1950 through 1995. Surface water was the source of 75 to 95 percent of all water withdrawals in the north-central States and consistently accounted for over 90 percent of total withdrawals in Illinois. From 1950 through 1995, the magnitude of increase in withdrawals from surface water was lower in Illinois than in most of the other north-central States, even though surface-water withdrawals in Illinois increased from about 9,000 to 19,000 million gallons per day. Total water withdrawals from ground water in Illinois have decreased by about 150 million gallons per day since 1975. From 1950 through 1995, from 68 to 86 percent of the total water withdrawals in Illinois were for generation of thermoelectric power; this percentage is higher than for the other north-central States and has increased since 1970. Approximately 12 percent of water withdrawals in Illinois are for municipal water supply, which was consistent with the other north-central States. Ten percent or less of the water withdrawn in the north-central States is estimated to have been consumed.