Estimates are made of United States resources of coal, petroleum liquids, natural gas, uranium, geothermal energy, and oil from oil shale. Accuracy of the estimates probably ranges from 20 to 50 percent for identified-recoverable resources to about an order of magnitude for undiscovered-submarginal resources. The total cost resource base in the United States is estimated to be about 3,200 billion tons, of which 200 to 390 billion tons can be considered in the category identified and recoverable. It is estimated that the total resource base for petroleum liquids is about 2,900 billion barrels, of which 52 billion barrels is identified and recoverable. Of the total resource base, some 600 billion barrels is in Alaska or offshore from Alaska, 1,500 billion barrels is offshore from the United States, and 1,300 billion barrels is onshore in the conterminous United States. Identified-recoverable resources of petroleum liquids corresponding to these geographic units are 11, 6, and 36 billion barrels, respectively. The total natural gas resource of the United States is estimated to be about 6,600 trillion cubic feet, of which 290 trillion cubic feet is identified and recoverable. Uranium resources in conventional deposits, where uranium is the major product, are estimated at 1,600,000 tonsmore » of U/sub 3/O/sub 8/, of which 250,000 tons is identified and recoverable. The resources of heat in potential geothermal energy sources are estimated to be greater than 10/sup 22/ calories, of which only 2.5 x 10/sup 18/ calories can be considered identified and recoverable at present. Oil shale is estimated to contain 26 trillion barrels of oil. None of this resource is economic at present, but if prices increase moderately, 160 to 600 billion barrels of this oil could be shifted into the identified-recoverable category. « less