There are over 14,000 oil and gas companies operating in the United States, most of which are small businesses. Some of the more well-known producers include Exxon Mobil, BP and Conoco Phillips. The 40 largest producers account for more than half of all domestic gas output.
The majority of natural gas coming from US-based drilling operations comes from the Marcellus Shale in Pennsylvania and Barnett Shale in Texas. The ten largest US natural gas drillers based on daily production volume are, from largest to smallest, Exxon Mobil, Chesapeake Energy, Anadarko, Devon Energy, BP, Encana, Conoco Phillips, Southwestern Energy Co., Chevron and Williams Energy.
These ten companies account for more than one-third of all the domestic natural gas production in the United States. The gas is produced by both traditional vertical drilling methods, as well as the more recently developed horizontal drilling or hydraulic fracturing.
To get an idea of how much natural gas is being produced by these companies, Exxon Mobil alone extracts an average of 3.9 billion cubic feet of natural gas each day, as of 2015. In 2010, Exxon Mobil extracted 26.1 trillion cubic feet of natural gas from US owned wells, contributing to their annual revenue of $370 billion.