That first map is misleading because it tops out at 530/square mile, which on an absolute scale is not very dense at all. For comparison, Tokyo metro houses 37

That first map is misleading because it tops out at 530/square mile, which on an absolute scale is not very dense at all. For comparison, Tokyo metro houses 37 million people at 11,300/square mile. NY/NJ/CT has 20 million people at 4,500/square mile. The nine Bay Area counties have a mean density of 1100/square mile. http://www.newgeography.com/content/002808-world-urban-areas-population-and-density-a-2012-update http://www.newgeography.com/content/002808-world-urban-areas... https://en.wikipedia.org/wiki/San_Francisco_Bay_Area https://en.wikipedia.org/wiki/San_Francisco_Bay_Area