The Haynesville Shale is located in parts of southwest Arkansas, northwest Louisiana and east Texas. It lies at depths of 10,500 to 13,000 feet below the land’s surface, becoming deeper to the south.

In 2008, the Haynesville Shale was thought to be the largest natural gas field in the lower 48 with an estimated 250 trillion cubic feet (7.1×1012 m3) of recoverable gas. According to the Energy Information Administration, Haynesville is the third largest shale play, now yielding around 6.3 Bcf/d and potentially holding nearly 500 trillion cubic feet of gas.