CHAMPAIGN, Ill. (AP) — The Mahomet Aquifer is a formation of sand and gravel that runs roughly from the Indiana state line west to the Illinois River in Cass County in west-central Illinois. It underlies parts of 14 counties, appearing on a map like a giant zigzag jutting southwest from near Danville to the Illinois River south of Peoria.

—The counties involving the aquifer are Cass, Champaign, DeWitt, Ford, Iroquois, Macon, Mason, McLean, Menard, Piatt Vermilion and Woodford.