The Bakken Formation is a major source rock in the United States portion of the Williston Basin. In this study, a large quantity of wire-line measurements was consolidated into a series of physical-property maps, with the intention of facilitating the regional study of the Bakken Formation and associated problems of hydrocarbon generation. Collectively, the maps depicts and partially quantify the increasing thermal maturity of the Bakken as it dips basinward. Present formation temperatures are roughly proportional to the level of thermal maturity, and resistivity values define where oil saturations are high.