Water levels, locations, depths, and aquifers tapped are given for 113 observation wells. Tabulated data include extremes of water levels for calendar year 1985 and for the period of record, pumpage of most major ground-water users in the State, and water-quality data from selected wells. The largest reported user of ground-water, the city of Lansing, pumped 7.9 billion gallons from the Saginaw Formation and glacial deposits in 1985.