However, those big empty places aren't quite as empty as they may seem... from a car, a plane. In my backpacking years I chose many a location for no other reason than their 'apparent' emptiness... only to discover they weren't actually that empty. Or at least how I would define 'empty'.

From deserts to plains to rugged forests it was seldom that I saw no indications of man.

I do not, however, deny that there does exist some empty locations, even by my definition. But I would say very few in the USA. - JamesJM