This report attempts to consolidate and provide information necessary for planning the development of mineral resources on the reservation. Such resources include petroleum and natural gas, coal, hypaum, phosphate rock, bentonite, and a variety of the more common construction and chemical materials. The principal income of the Wind River tribes over the years has come from oil production. However, oil production on the reservation probably has passed its peak, and revenues from this source are expected to decline gradually in future years. Development of other mineral resources could offset this anticipated decline in tribal income and maintain, or even improve, the economy of the reservation.