The extreme high density of the central portions of the New York area

Sprawl supporters like Wendell Cox and Robert Bruegmann¹ (and many other writers) have gleefully pointed out the Census Bureau’s somewhat counterintuitive claim that the Los Angeles urban area is denser than New York’s. Anyone familiar with Los Angeles and New York would understand that the explanation for this must lie mostly in the different characters of the outlying portions of the two urban areas. New York (like other eastern cities) includes a large number of suburban areas with two-or-more-acre zoning. Such low-density suburbs are almost impossible in western cities, where rough terrain and government ownership of much of the mountainous land have discouraged their formation.

One way of demonstrating the extraordinary density of New York’s central portions that I haven’t seen pointed out requires looking at 2010 population density by census tract for all 73,000-odd U.S. census tracts (data from NHGIS). The densest tract, with 196,409 people per square kilometer (508,697 people per square mile), turns out to be in Chicago: a tract created especially for the 2010 census that contains a single apartment building, at 5415 North Sheridan Road. 163 out of the next densest 166 tracts, however, are in the New York area (all but one in New York, N.Y.; the three non-New-York tracts are in San Francisco). New York’s overwhelming dominance extends down the density hierarchy. Out of the 436 census tracts in the United States with population densities of more than 30,000 people per square kilometer (77,700 per square mile), 409 are in the New York area (401 in New York City). Of the remaining 27, 12 are in the San Francisco Bay Area (11 in San Francisco), 6 in Los Angeles County, 5 in Chicago, 3 in Honolulu, and 1 in Baltimore. Of the 967 tracts with more than 20,000 persons per square kilometer (51,800 people per square mile), 867 are in the New York area (842 in New York City). (The runners-up are: Los Angeles County 29, Cook County (almost all in Chicago) 24, San Francisco Bay Area 22, Honolulu 7, Philadelphia 6, Washington area 5.)

Here are choropleth maps of the New York, Chicago, Los Angeles, San Francisco, and (just for fun) Toronto areas, all at the same scale, showing persons per square kilometer in 2010 (2011 in Toronto) with the same class intervals and colors. Note how different New York looks. There are, for example, hardly any signs of “population densities as high as [in] Manhattan” that some scholars² have claimed for Los Angeles. All of these metropolitan areas are radically underbounded, but outlying areas (even in Los Angeles) never get beyond moderate densities.

This observation jibes completely with the Census Bureau’s recent creation of a “population-weighted density” statistic for urban areas, in which the New York area ends up being considerably denser than any other American urban region. New York has 31,251 “population-weighted” persons per square mile, San Francisco 12,145, Los Angeles 12,113, and Chicago 8,613—and these figures include the suburbs.