The objectives of the hydrologic investigation in Griggs and Steele Counties, N. Dak. (fig. 1) were to: (1) determine the location, extent, and nature of the major aquifers; (2) evaluate the occurrence and movement of ground water, including recharge and discharge; (3) estimate the quantities of water stored in the aquifers; (4) estimate the potential yields of wells tapping the major aquifers; and (5) determine the chemical quality of the ground water.