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 Uinta-Piceance Province is located in eastern Utah and western Colorado, encompassing all or parts of Delta, Garfield, Gunnison, Mesa, Moffat, Montrose, Ouray, Rio Blanco, and Routt Counties in Colorado and all or parts of Carbon, Duchesne, Emery, Grand, Sanpete, Sevier, Uintah, Utah, and Wasatch Counties in Utah. The main population centers within the study area are Grand Junction and Rifle, Colo.; and Price and Vernal, Utah. The main highways, I-70 and U.S. 40, generally traverse the area from east to west. The Green River and Colorado River and their tributaries drain the area. For this study the Uinta-Piceance Province includes the Wasatch Plateau. The province boundary was drawn to include the geologic structures generally considered to be in or bounding the Uinta Basin and Piceance Basin.