Gastar Exploration, Inc. is an independent energy company. The Company is engaged in the exploration, development and production of oil, condensate, natural gas and natural gas liquids (NGLs) in the United States. Its principal business activities include the identification, acquisition, and subsequent exploration and development of oil and natural gas properties with a focus on unconventional reserves, such as shale resource plays. The Company's properties consist primarily of oil and natural gas leases in mid-continent area of the United States in Oklahoma. It holds a concentrated acreage position in the core of the STACK Play, an area of central Oklahoma which is home to multiple oil and natural gas-rich reservoirs, including the Meramec and Osage formations within the Mississippi Lime, the Oswego limestone, the Woodford shale and Hunton limestone formations.