Ultra Petroleum Corp. (Ultra) is an oil and gas company. The Company is engaged in the development, production, operation, exploration and acquisition 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. The Company conducts its operations in the United States. The Company focuses on sands of the upper Cretaceous Lance Pool in the Pinedale and Jonah fields. The Lance Pool includes sands of the Lance formation at depths between approximately 8,000 and 12,000 feet and the Mesaverde formation at depths between approximately 12,000 and 14,000 feet. As of December 31, 2016, the Company owned oil and natural gas leases totaling approximately 105,000 gross (69,000 net) acres in southwest Wyoming's Green River Basin.