Shale gas reserves in the U.S. 2021, by basin
The Appalachian Marcellus basin has the greatest proved reserves of any shale play in the United States. As of 2021, proved natural gas reserves in that area amounted to nearly 145 trillion cubic feet, nearly twice the size of the second-largest shale play in the Permian Basin. Marcellus was responsible for nearly 10 trillion cubic feet in shale gas production in 2021.
