Even saying something like "California has a lot of people" can mislead you if you look at a map of the state. I live in Michigan and fly into Silicon Valley about twice a year; when I depart Michigan the entire state I fly over shows signs of human population, as everything is at least a farm [1]. In Silicon Valley, most of those mountains you can see on the horizon have nothing (visible from a plane) on the other side of them. Even most of California is empty mountain.

[1]: I have to qualify it with "the parts I fly over" because obviously I'm flying over the southern part of the state. Head north and you start getting vast tracks of wilderness, and the upper peninsula is effectively not populated. There's just a few beads of "civilization" tied together by some fairly long roads, which are themselves most of the rest of the "civilization", and then it's square mile after square mile of wilderness.