The Urbanist Musings of Pete Saunders

CSY At Forbes: The Urban Growth Debate: Cities, Suburbs, Exurbs

A view of downtown San Jose, CA. Is it the nation’s tenth largest city, or the largest “suburb” of the Bay Area? Source:

Ever since cities began their resurgence some 25-30 years ago, there’s been increasing debate over what facet of the metro area is actually doing the growing. For most of the post-World War II years population growth was undeniably the purview of the suburbs. As older suburbs matured, new suburbs emerged and soon they were the focus of growth. Which brings us to where we are now, with cities that are showing strong growth after decades of population loss.

So, which is growing? Is it cities? Is it traditional suburbia just beyond the city limits? Is it the suburban periphery? The answer is yes – all of the above. It depends on your metro.

I took a look at the thirty largest U.S. metros (those with more than two million) and looked at growth rates within them between 2010 and 2016. But in doing so, I looked at growth within metro components that are often considered, or analyzed as such. Doing so begins to get to a resolution of the issue.

Most people are familiar with two components of metro areas: core or principal cities that serve as the hub of the metro, and the collection of counties surrounding it that form the balance of the metro area. The balance beyond the core city typically includes all suburban and peripheral areas of the metro area. Most people, however, are far less aware of an intermediate component that, if utilized, can help us gleans some facts. The U.S. Census also designates urbanized areas – the contiguous land area that includes all census tracts with population greater than 1,000 persons per square mile. This includes virtually all core cities and most, but not all, of suburbia.

With that in mind, I split the 30 largest U.S. metros into three buckets for which data could be acquired: core cities, an intermediate suburban area that is the balance of the urbanized area without the core city, and then the balance of the metro area beyond the core city and urbanized area boundary. That third slice, at the edge of metro areas, is what I call the exurban area or the suburban periphery.

Take a look below at the following tables, which show the percentages of core city (red), suburban (yellow) and exurban (green) populations by metro, first in 2010:

Largest U.S. Metros by core city concentration, 2010

And then again in 2016:
Largest U.S. Metros by core city concentration, 2016

The top of the list includes expansive Sun Belt cities with plenty of land available within the city limits (San Antonio, San Diego), and traditional big cities that are much more dense than their surroundings (New York, Chicago). The bottom of the list includes core cities that have become hemmed in by suburban incorporation and as a result have been limited in their ability to grow relative to the rest of their respective regions. Atlanta, Miami, St. Louis and Washington, D.C. each exhibit those traits.

To compare population change by metro area component, I developed this table:

City, Suburban and Exurban Growth Rates, 2010-2016

Nationally for the largest metros, population growth was pretty evenly distributed among the metro components. Core cities grew by 5.8% between 2010-16, intermediate suburbs by 6.1%, and exurbs by 5.6%. There’s no real pattern here, but there’s enough going on in all corners that if you want to highlight a particular metro area component as the American preference, you can find it. In all, eleven of the thirty largest metros show their growth being led by their core cities, with several of today’s superstar cities (New York, Seattle, Washington, D.C., Boston) leading the way. Another nine metros show their strongest growth in the intermediate suburbs. This diverse group includes Portland, Baltimore, Charlotte and Sacramento. The remaining ten metros show their strongest growth occurring at the suburban periphery. Most are Sun Belt metros like Dallas and Phoenix, or Rust Belt metros like St. Louis and Cleveland, but the Bay Area stands out as an exurban outlier among the nation’s superstar metros.

To try to make some sense of the data, I grouped the metros by their overall rates of growth. Those that grew at nine percent or more were characterized as high growth metros; those that grew between three and nine percent were deemed moderate growth metros; and those that grew at less than three percent were called low growth metros. Grouping them in this manner, and identifying the single component leading population growth for each metro, led to this table:

Largest U.S. Metro Growth by area type, 2010-2016

Put it all together, and what does it mean? It means that if anyone tells you that Americans express a clear preference for any kind of lifestyle, whether city or suburban or exurban, there are dozens of counterexamples to be found. Each has their strengths and weaknesses, their advocates and critics. Each will have to find their own path to realize their potential.

3 Responses to “CSY At Forbes: The Urban Growth Debate: Cities, Suburbs, Exurbs”

  1. lewyn

    Very interesting, but one caveat: in 2010, many central cities had far less growth in the Decennial Census than in mid-decade estimates, which indicates that perhaps ACS overestimated core growth. (Then again, it is not clear whether the 2020 Census will be as useful a data source as the 2010 Census).


  2. FDW

    This is my first time posting, though I've been reading and enjoying this blog for some time. The Bay Area's oddball status I see as being a result of two countervailing factors: Rabid NIMBY's trying to drown the region in amber, and tech tycoons who want to hire every warm they can. More of the growth is happening on the edge because that's the only place where it's not completely impossible (Though far from easy). This would be even more obvious by using the CSA numbers rather than the MSA ones. And in my opinion, the CSA numbers are more representative of the Bay Area, because the Mountains and Water geography fractures what's really a coherent Metropolitian Area. It's also the reason why the three biggest subsections (San Francisco, Oakland, and San Jose) have such strong individual identities. In other Metro Areas of the same age as SF, the Industrial and Auto Era zones wound up as cocentric rings, but SF's lack of flat land (and for California, Balkanized counties) meant that these areas developed semi-independently, economically intertwined but physically isolated enough from SF that political consolidation failed to happen.



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