Given the population and size of the United Kingdom (64,100,000 in 2013, over 94,060 sq mi, for an average density of 661.9/sq mi), or California (38,802,500 in

Given the population and size of the United Kingdom (64,100,000 in 2013, over 94,060 sq mi, for an average density of 661.9/sq mi), or California (38,802,500 in 2014, over 163,696 sq mi, av. density 246/sq mi), I'm not sure I'm inclined to agree that the US (320,206,000 people in 3,531,905.43 sq mi, av. 88.6/sq mi) has quite that modest a sensible capacity. Of course, not every square mile is equal - water is a vital component that's set to become a very pressing topic in interstate negotiations in the coming decades.