U.S. City Size, Density, & Population Change, 1950 to 2022 – and the Dream of the “15-Minute City”

Many environmentalists now advocate the development of “15-minute cities,” urban areas dense enough to allow residents “to access most of the places [they] need to go within a 15-minute walk or bike.” This vision has much to recommend it. Many people find neighborhoods of this sort deeply attractive, both as places to live and visit. I count myself among them. My ideal living arrangement would be to divide my time between an apartment in such a city and a house in a remote rural area. Instead, like most Americans, I live in a medium-density suburban environment – which sometimes seems to offer the worst of both worlds.

But although I understand the appeal of 15-minute cities, I also recognize that creating them would be extraordinarily difficult if not impossible in the United States. Evidence from both polling and actual residential choice indicates that most Americans dislike dense cities and prefer suburban living. Ironically, moreover, environmentalists themselves are one of the main obstacles to the urban intensification that such a vision requires. Construction projects of all sorts, after all, often face environmental lawsuits, which can bring them to a quick halt.

An equally severe problem is the fact that the few cities in the United States that approach the required degree of walkability have been deintensifying, shedding residents over the past several years. From 2020 to 2022, New York City lost 3.5 percent of its population, Philadelphia 2.3, Chicago 3.0, and San Francisco a shocking 7.5. This decline was at first mostly a matter of people fleeing crowded conditions during the COVID pandemic, but it is now being driven primarily by safety and property-security concerns. For the same reasons, many of the mass-transit systems that are required for urban intensification are losing ridership and find themselves financially troubled. As a result, it is difficult to avoid the conclusion that, at least in the United States, the 15-minute city is little more than a fond dream.

Some of the maps that I have been making for my prospective historical atlas of urban development in the United States might prove useful in examining the urban growth and density issues surrounding the 15-minute city idea. These maps, to be sure, are unusual, as they depict no geographical features beyond city size and density. The spatial patterns that they show are also wildly distorted. As a result, they might more properly be regarded as graphic visualizations. But I still view them as maps, as all GeoCurrents posts focus on map explication.

The first map shows the size, density, and rough relative locations of the twenty most populous cities, as formally defined, in the United States in 2022. The numbers in the bottom corners of each urban polygon indicate the population growth rate, in percentage terms, of that city from 2010 to 2020 (left) and from 2020 to 2022 (righ). As can be seen, most large American cities lost population in the latter period. More important, such losses were concentrated in more densely inhabited cities. Several of the more sparsely settled cities, in contrast, gained population during this period. But as can also be seen, all these cities added residents from 2010 to 2020, some of them to a significant degree. This was true even in the country’s most densely inhabited urban areas. New York grew in this period by 7.7 percent and San Francisco by 8.5 percent. But with the exceptions of Seattle and Denver, all cities expanding by more than ten percent from 2010 to 2020 are characterized by low population density.

The overall impression conveyed by this map is one of low population density in America’s largest cities. Some of them have annexed such extensive suburban and rural hinterlands that they do not really count as cities in the informal sense. Jacksonville, Florida, for example, consolidated with Duval County in 1968, and as a result, its 971,319 residents live in a “city” that sprawls over 874.46 sq mi. This gives Jacksonville a population density of 1,270.73/sq mi, a figure lower than that of the typical American inner suburb. The contrast between Jacksonville and San Francisco is instructive. Although the city of San Francisco is also consolidated with its county, its population density is of an entirely different magnitude. In 2022, San Francisco’s 808,437 residents inhabited an area of 46.9 sq mi, giving it a density of 17,237.5/sq mi. But if San Francisco is thickly populated by U.S. standards, it is not by that of New York City. In 2020, Manhattan had 1,694,251 residents living in an area of 22.83 sq mi, giving it a density of 74,780.7/sq mi.

As the next map shows, in 1950 the 20 largest cities in the United States were considerably denser that those of 2022. 1950 was arguably the heyday of American urbanism. Driven in part by the war-economy of the first half of the decade, all large U.S. cities grew during the preceding census interval, some by considerable margins. Extremely rapid growth occurred both in sparsely inhabited cities (see Houston on the map below) and in densely settled ones such as San Francisco and Washington, DC.

Seven cities are found on the lists of the 20 largest U.S. cities in both 1950 and 2022. As can be seen on the map posted below, the country’s two densest major cities, New York and San Francisco, experienced relatively little change in either population size or density in the intervening 72 years. Two relatively densely settled cities, Chicago and Philadelphia, saw significant populations losses in the same period, reducing their densities. In contrast, two West Coast cities, Seattle and Los Angeles, experienced major increases in both population and density. Houston, in contrast, saw a huge population increase but did not more into a higher population-density category, as it also expanded in area.

The next map, indicating population size but not density, shows which cities dropped out of the top-20 list between 1950 and 2022 and which ones were added to it. The geographical pattern seen here is stark but not surprising. Except for New Orleans, all the “drop-out” cities are in the northeastern quadrant of the country. In contrast, with the exceptions of Indianapolis and Columbus, all the additions are in the southern half of the country. Interestingly, Columbus has many attributes of a sunbelt city, although it experiences very little sunshine from November through March. The concentration of emergent, low-density, large cities in Texas is also noteworthy.

The final map addresses a question that probably crossed the minds of some readers: where are such major cities as Atlanta or Miami? With just under half a million residents, Atlanta is not a particularly large city, although its metropolitan area certainly is. The same patterns holds for Miami. The map below thus shows the locations (but not the populations) of cities that anchor metropolitan areas in the top 30 by population in 2022, but did not themselves place in the top-20 city lists of either 1950 or 2022. It is not coincidental that three of the eight are in booming Florida.

The first two maps in this post are somewhat misleading, as they do not adequately convey the population density of New York. To do so properly, the city must be broken down into its five constituent boroughs. This will be done for the next GeoCurrents post.

U.S. City Size, Density, & Population Change, 1950 to 2022 – and the Dream of the “15-Minute City” Read More »