We are an independent oil and natural gas company engaged in the exploration, exploitation, acquisition, development and production of onshore U.S. oil and natural gas properties with a focus on shale resource plays. Our principal operations are conducted in certain key U.S. oil and natural gas areas including Texas, Louisiana and the Appalachia region. The following is a brief discussion of our producing regions:
East Texas and North Louisiana
The East Texas and North Louisiana regions are primarily comprised of our Haynesville and Bossier shale assets. We have a joint venture with a wholly owned subsidiary of Royal Dutch Shell, plc, covering an undivided 50% interest in the majority of our Haynesville and Bossier shale assets in East Texas and North Louisiana. The East Texas and North Louisiana regions also include certain assets outside of the joint venture in the Haynesville and Bossier shales. We serve as the operator for most of our properties in the East Texas and North Louisiana regions.
The South Texas region is primarily comprised of our Eagle Ford shale assets. Our position in this region includes approximately 48,500 net acres, of which approximately 95% are held-by-production. We serve as the operator for most of our properties in the South Texas region.
The Appalachia region is largely comprised of our Marcellus shale assets. Our operations in the Appalachia region have primarily included testing and selectively developing the Marcellus shale with horizontal drilling. As of December 31, 2018, we held approximately 339,800 net acres in the Appalachia region, including approximately 234,800 net acres prospective for the Marcellus shale and approximately 69,000 net acres prospective for the dry gas window of the Utica shale in Pennsylvania. We serve as the operator for most of our properties in this region.