The Minerals Management Service is part of the US ministry of the Interior and is headquartered in Washington, D.C. It includes two major programs, Offshore Energy and Minerals Management and Minerals Revenue Management. The Offshore program, which manages the mineral resources on the OCS, comprises three regions: Alaska, Gulf of Mexico, and the Pacific. The MMS plays a key role in America’s energy supply by managing the mineral resources on 1.76 billion acres of the Outer Continental Shelf (OCS). The OCS is a significant source of oil and gas for the Nation’s energy supply. The approximately 43 million leased OCS acres generally accounts for about 15 percent of America’s domestic natural gas production and about 27 percent of America’s domestic oil production. The MMS’s oversight and regulatory frameworks ensure production and drilling are done in an environmentally responsible manner, and done safely. The offshore areas of the United States are estimated to contain significant quantities of resources in yet-to-be-discovered fields. MMS estimates of oil and gas resources in undiscovered fields on the OCS (2006, mean estimates) total 86 billion barrels of oil and 420 trillion cubic feet of gas. These volumes represent about 60 percent of the oil and 40 percent of the natural gas resources estimated to be contained in remaining undiscovered fields in the United States.