This paper discusses the regional geology and hydrology of the Hanford Reservation with emphasis on the characteristics of the Lower Ringold Formation and the Columbia River Basalts and interbeds. These formations constitute the uppermost confined flow systems underlying the Hanford Reservation. Work shown in this paper leads to the conclusion that these aquifers are rather extensive and that they are interconnected especially along the Umtanum-Gable Anticline. Recharge into the confined aquifers appears to occur at the fringes of the Pasco Basin. The eastern portion of the Hanford Reservation appears to be a discharge area for these aquifers. Areas of monoclinical downfolding such as Cold Creek Valley appear to act as flow barriers, thus helping to build up the pressure in the uppermost confined aquifers.