Oil and gas are explored for and developed by private corporations. There are many small companies within Indiana that conduct this type of work, many of which are based in the southwest portion of the state. Listings of such companies are available on the Operators Listing of the Indiana Department of Natural Resources, Division of Oil and Gas, and also from the Indiana Oil and Gas Association (phone: 812-432-8061). The latter is a trade organization that includes many operators working within the state.