The last 20 yr of the Rocky Mountains oil and gas exploration and production business have been turbulent. Most of the major companies have left; they have been replaced with, independents and small to larger private and public companies. Natural gas become the primary focus of exploration. A discussion covers the shift of interest from drilling for oil to gas exploration and development in the Rockies since 1980; resource pyramid, showing relative volumes, reserves, resources, and undiscovered gas; the Wyoming fields that boost US gas supply, i.e., Jonah (6-12 tcf), Pinedale Anticline (10-20 tcf); Big Piney-LaBarge (15-25 tcf), Madden (3-5 tcf), and Powder river (24-27 tcf); and the future.