Anything you plot in the USA that has a strong correlation with numbers of people ends up looking like the distribution on your map.<p><a href="http://www.mapofusa.net/us-population-density-map.htm" rel="nofollow">http://www.mapofusa.net/us-population-density-map.htm</a>
Interesting. I wonder if it correlates strongly to (non-satellite) broadband uptake?<p>There seems to be a pretty clear dividing line at the Mississippi, beyond what I would have guessed would have existed simply due to population density.