Southwestern Energy Company is an independent energy company engaged in exploration, development and production activities, including the related marketing of natural gas, oil and natural gas liquids (NGLs) produced in its operations. The Company operates through two segments: Exploration and Production (E&P) and Marketing Services. The Company's operations are principally focused on the development of unconventional natural gas reservoirs located in Pennsylvania and West Virginia. The Company’s primary business is the exploration for, and production of, natural gas, oil and NGLs, with its operations solely within the United States. The Company is focused on the development of natural gas reservoirs located in Pennsylvania and West Virginia. Its operations in northeast Pennsylvania are primarily focused on the natural gas reservoir known as the Marcellus Shale, and its operations in West Virginia and southwest Pennsylvania.