The USGS Central Region Energy Team assesses oil and gas resources of the United States. The onshore and State water areas of the United States comprise 71 provinces. Within these provinces, Total Petroleum Systems are defined and Assessment Units are defined and assessed. Each of these provinces is defined geologically, and most province boundaries are defined by major geologic changes. The Wind River Basin Province is located in central Wyoming, encompassing all or parts of Hot Springs,Fremont, and Natrona Counties. The main population centers within the study area are Casper, Riverton, and Thermopolis, Wyoming. The main highway, I-25 traverses the area to the east of the study area from north to south. The Wind River and South Fork of the Powder River and their tributaries drain the area. The province boundary was drawn to include the geologic structures generally considered to be in or bounding the Wind River Basin.