Few American Cities Are Truly Dense. We Can Do Better.

American city planners generally agree on the desirability of dense cities. Dense cities, with many people living in compact areas, are important as focal points of economic and cultural innovation, and also as places where residents voluntarily adopt housing prototypes and lifestyle patterns that have lower-than-average greenhouse gas emissions.

Thus, it’s sobering to look at the 2020 Census results and ask how many dense cities the U.S. actually has. As I discuss in a new report for the Manhattan Institute, the answer is not many. Only 12 of the nation’s 50 largest central cities had as many as 7,500 residents per square mile in 2020 — the average population density for U.S. central cities in 1950. Many other cities have a neighborhood or two that’s dense and walkable, where residents can stroll to shopping and services. But the number of cities where a sufficient number of such neighborhoods exist to pull the overage population density up to 7,500 per square mile are few.

How did we get from 1950’s relatively high densities to today’s sprawl? It’s a well-known story. Americans flush with postwar prosperity didn’t value what they had. They built highways with a flood of federal aid — demolishing urban housing while fueling suburban growth, mostly single-family homes that also were heavily subsidized. Older cities lost population or grew by annexing the new suburbs. Houston, the nation’s fourth-largest city in 2020, quadrupled its land area in the 70 years after 1950 but never got very dense (3,599 residents per square mile in 2020). Once-dense cities like Baltimore, Detroit and Milwaukee didn’t annex their suburbs and saw their populations and densities plummet.

The 12 cities cited in my report all overcame the general tendency to push growth to the metropolitan periphery, at very low densities, and grew denser within established city boundaries. All gained housing units between 2000 and 2020, and all but Chicago gained population in that period. Some grew remarkably fast: Miami increased housing units by 43 percent over two decades, Seattle by 36.1 percent and Washington, D.C., by 27.5 percent. New York didn’t grow as fast, but it grew by a lot, adding 796,000 people, more than the entire population of all but 17 U.S. cities.
How did they do it? I found that many cities that kept growth within city limits employed a “grand bargain” strategy, in which growth is targeted at relatively high densities to a limited area of the city where there are few existing residents to object. Such areas might be formerly industrial but now disused, or surplus land once used for public facilities.

I had earlier noted the highly skewed pattern of population growth from 2010 to 2020 in New York City, with big gains in a handful of the city’s 59 community districts, mainly as a consequence of rezoning under former mayors Rudolph Giuliani and Michael Bloomberg, but many others growing little. It turns out that many other cities grew via a similar strategy. Washington, for example, saw much of its growth in the Sixth Ward, an area forming a semicircle around Capitol Hill, in locations where few lived before. Miami’s growth was focused on a swath east of Interstate 95, in and around the downtown. San Francisco’s population growth was directed to formerly nonresidential areas adjacent to the bay front.

In all these cities, many established residential areas were protected from growth by restrictive zoning – the “bargain” in which the city gets the economic benefit from growth while sparing existing residents from experiencing change and disruption. That works politically, but has downsides. New housing development occurs mostly at high densities and excludes the housing types that are cheaper to build and thus to buy or rent, such as two- or three-family attached homes, small multifamily walkups and garden apartments. New housing is designed for a specific market — often younger professionals — and may not adapt easily to changes in demand. Finally, the supply of noncontroversial building sites is generally limited. As the city continues to grow, it needs a different strategy, one that likely will bring change to established neighborhoods.

The standouts among the 12 dense cities have crossed that threshold and begun to think about “distributed growth” strategies, in which new housing is built in many neighborhoods and not just a few. One strategy to disperse growth was Seattle’s designation of "urban centers," "hub urban villages" and "residential urban villages" where growth is to be concentrated, with a conceptual hierarchy of scale from very dense to more moderate. This still led to concentrated growth, but affected more parts of the city. Boston successfully encouraged construction of new housing for affordable to middle-income households, without subsidies, near dispersed transit stations. Minneapolis has designated commercial corridors for growth, while permitting up to three units on all single-family lots.

Distributed growth is perhaps more easily accomplished through a comprehensive planning process to secure public buy-in, with upgraded transit and attention to the quality of other neighborhood infrastructure and amenities. “Grand bargain” planning is good, and no city should give up the opportunity to do it where possible. However, the rewards for cities that succeed in distributed growth include more gradual and varied neighborhood change, new housing affordable at a wider range of incomes without subsidies, and greater perceived equity in the distribution of the burdens of population growth.

Eric Kober is a senior fellow at the Manhattan Institute. He retired in 2017 as director of housing, economic and infrastructure planning at the New York City Department of City Planning.