The U.S. Geological Survey, in cooperation with the Alabama Department of Environmental Management, is conducting a series of geohydrologic studies to delineate the major aquifers and their susceptibility to contamination in Alabama. This report delineates and describes the geohydrology and susceptibility of the major aquifers to contamination in Area 8--Autauga, Chilton, Elmore, Lowndes, and Montgomery Counties. The major aquifers in the study area are the Eutaw, Gordo, and Coker aquifers of Cretaceous age. One or more of these aquifers are sources of public water supply in each of the five counties. The recharge areas for these aquifers are in Autauga, Chilton, Elmore, and Montgomery and Prattville. Maximum groundwater use in the Prattville area is more than 8 mgd (million gallons per day). Estimated maximum groundwater withdrawal for all uses in the study area is about 65 mgd. The potentiometric map of the Gordo aquifer indicates that the Alabama River may serve as a recharging boundary to the Gordo aquifer along the flood plain of the river in the Montgomery-Prattville area. The river also is acting as a recharging boundary to the Eutaw and Coker aquifers, where the potentiometric surfaces in the aquifers have been lowered. All recharge areas for the major aquifers are susceptible to contamination from the surface. However, the areas that are highly susceptible to contamination extend from Jemison to Clanton in Chilton County where the Coker aquifer generally is < 100 ft below land surface, and the flood plains of the Alabama, Coosa, and Tallapoosa Rivers, which are underlain by alluvial deposits that are in hydraulic contact with the major aquifers. Within the highly susceptible areas, the areas especially susceptible to contamination are the flood plain of the Alabama River in the Montgomery area and the flood plain of the Tallapoosa River. Pumpage from the major aquifers in this area has significantly lowered the potentiometric surface in the aquifers resulting in a downward gradient between the major aquifers and the Alabama River and the alluvial deposits underlying the flood plain along the river. (Lantz-PTT)