Ultra Petroleum Corp., an independent oil and gas company, engages in the acquisition, exploration, development, operation, and production of oil and natural gas properties. Its principal business activities are developing its natural gas reserves in the Green River Basin of southwest Wyoming?the Pinedale and Jonah fields; its oil reserves in the Uinta Basin in northeast Utah; and its natural gas reserves in the north-central Pennsylvania area of the Appalachian Basin. As of December 31, 2016, the company owned interests in approximately 105,000 gross acres in Wyoming; and 144,000 gross acres in Pennsylvania. It also owns approximately 8,000 net acres in the Uinta Basin in Utah. The company was founded in 1979 and is headquartered in Houston, Texas. On April 29, 2016, Ultra Petroleum Corp., along with its affiliates, filed a voluntary petition for reorganization under Chapter 11 of the United States Bankruptcy Court for the Southern District of Texas.