Water levels, locations, depths, and aquifers tapped are given for 117 observation wells. Tabulated data include extremes of water levels for 1982 and for the period of record, pumpage of most major ground-water users in the State, and quality data on selected wells. The largest reported user of ground-water, the city of Lansing, pumped 8.2 billion gallons from the Saginaw Formation and glacial deposits.