How Many People Can Fit In NYC?

The New York Times looks at shrinking densities:

As crowded as the city feels at times, the present-day Manhattan population, 1.6 million, is nowhere near what it once was. In 1910, a staggering 2.3 million people crowded the borough, mostly in tenement buildings. It was a time before zoning, when roughly 90,000 windowless rooms were available for rent, and a recent immigrant might share a few hundred square feet with as many as 10 people. At that time, the Lower East Side was one of the most crowded places on the planet, according to demographers. Even as recently as 1950, the Manhattan of “West Side Story” was denser than today, with a population of two million.

On weekdays Manhattan's population roughly doubles to 3.9 million.