If it’s by metro area density, LA wins. If by weighted density and other density metrics, NYC. Having living in the metro areas of both ( LA right now and NYC earlier on), the latter is not very dense but is consistent in suburban density over a large area. I live 1-2 hours away from Downtown and the same development goes on for miles almost radiating from the coast and continues down the coast to an extent. Reminded me of a larger South Florida.
New York’s density is most intense in the core, including the Five Boroughs and Hudson County. Some smaller dense cities and towns exist beyond that, like Newark and Yonkers, but there’s no consistent density in between many of these places unless they are in the path connecting NYC to the rest of the Megalopolis. I remembered driving through NJ one time to get to the city for Thanksgiving week and it was very rural in certain parts before immediately reaching Newark’s ring of influence. Out of the 20 million that live in the Tri-state Area, 11 million or more live within the intensely lit area in the bottom of this picture.
https://en.m.wikipedia.org/wiki/New_...ropolitan_area