American has a maximum sustainable carrying capacity of 50 Million People
Dependence on Phantom Carrying Capacity
by William R Catton, Jr
It should be clear that the actual population of the United States has already overshot its carrying capacity as measured by the energy-producing capability of visible American acreage. To achieve genuine self-sufficiency in energy depending on visible acreage only, the population of America would have had to level off no later than 1880 at 50 million people.