Maps that show contours of the altitude of water levels for wells completed in the Mississippi River Valley alluvial aquifer in eastern Arkansas were prepared using water-level measurements made in the spring of 1972-1980. Hydrographs for selected wells are included to show trends and lack of trends in water-level changes. The aquifer consists of gravel and sand in flood-plain and terrace deposits of Quaternary age. The aquifer supplies much of the water used for irrigation and aquaculture in eastern Arkansas. A large depression in the potentiometric surface caused by pumping for irrigation and aquaculture occurs in Arkansas, Lonoke, and Prairie Counties. A smaller depression in the potentiometric surface occurs north of Brinkley. Significant water-level declines occurred during the period 1972-80 in several counties west of Crowleys Ridge. (USGS)