[bobthepanda]

You also don't even have to urbanize all that much to get higher density.

Nassau County in New York is one of the birthplaces of postwar suburbia and has a population density higher than Los Angeles County, ranking at 22nd in the country. (4,705 people per square mile vs 2,420.)

[gottorf]

To be fair, LA County includes mountains (Angeles National Forest among others) and a desert and a whole lot of nothing on the other side of those mountains. Nassau County is almost all developable land.

I bet if you compared like to like, the density won't be too far off.