Image by Mark Strozier licensed under Creative Commons.

Across the US, people flocked to urban cores in the early 2010s. But lately, growth has picked up in outer, less dense suburban places, particularly in the nation’s most sprawling metro areas in the South and Southwest.

This comes from the Census Bureau’s 2016 population estimates for the nation’s metropolitan areas and counties, which came out in March. Along with other Census products like the American Community Survey, the population estimates fill in the gaps between each decennial census, helping demographers, businesses, and public officials understand population trends in their communities. Also, some government programs that allocate funding on a per capita basis use the annual population estimates to update the funding amounts they give to each jurisdiction.

Across the country, sprawl is beating out density

For urbanists, the 2015-2016 estimates present a double-whammy of concern: growth in large, dense urban counties has slowed down significantly, and it has picked up in low-density, sprawling suburban places.

Many of these fast-growing, sprawling places are located in the “Sunbelt” metropolitan areas in the South and Southwest:

In large, dense urban counties, many existing residents are moving out

An area’s population can change as a result of “vital events” (births and deaths) or from migration (people moving from one place to another). In most places, the net population change from vital events tends to be fairly stable year-over-year; in DC, for example, the Census estimates that births have outnumbered deaths by 4,200-4,500 every year this decade, accounting for about 26,000 young new residents.

But migration trends, whether foreign (i.e., immigration) or domestic (i.e., within the US) often vary more widely. In 2010-11, DC added a net gain of about 1,800 immigrants; in 2015-16 the net gain had more than doubled to 4,100.

What seems to be stunting urban growth—and propelling Sunbelt growth— is a shift in domestic migration trends. For example, Maricopa County, AZ (home to Phoenix) posted a net gain of more than 43,000 residents last year who moved there from other parts of the US—nearly three times the 15,000 Maricopa added during 2010-11.

By comparison, the five counties that comprise New York City experienced a net loss of more than 121,000 people to domestic migration last year, more than double the 56,000 who left between 2010 and 2011, and nearly 30,000 more than from 2014-2015. The map below illustrates the 2015-16 domestic migration trends, with green counties gaining people while orange counties lost them.

On the Move

Image from the US Census Bureau

Two trends stand out: one, most rural counties, especially in the Midwest and Great Plains, are losing population to other areas of the US. Two, in addition to New York City, most of the nation’s largest, densest counties are losing people to other regions.

In the map above, notice the dark orange clustered in places such as Cook County, IL (Chicago); Los Angeles, San Diego and several Bay Area counties in California; Miami-Dade County, FL; Suffolk County, MA (Boston); and Fairfax, Montgomery, and Prince George’s Counties surrounding DC. In these locations, the county lost at least 5,000 residents during 2015-16 due to residents moving away to another county.

Note, though, that the District itself is bucking the national trend: the Census estimates that about 2,300 more people moved into DC than moved out during 2015-16.

Why are more people leaving than moving into these areas? For the coastal metropolitan areas, at least, one likely contributing factor is high housing costs thanks to low supply. The problem, in short, is not enough housing is being built where it is critically needed.

Why do growth trends matter?

Population growth impacts a community in a variety of ways. Generally speaking, on the positive side, growth can spur widespread benefits across an entire region and expand economic opportunities. More specifically, growth can provide:

  • More job opportunities for residents, and a wider and more diverse pool of potential talent for employers.
  • More customers for existing businesses and favorable conditions for founding new businesses.
  • Improved revenues for local governments, which may allow increased services without increasing tax rates.
  • Larger funding allocations from federal formula programs.

Losing people, on the other hand, can mean missing out on the above, along with the problem of having fewer people to cover the costs of infrastructure built for a bigger population. Of course, growth can also put pressure on a region by stretching public services like schools or utility networks. The answer, though, is not to limit growth, but to manage it well.

Should these trends continue, the Fort Worths, Scottsdales, and Atlantas of the world will need to continue to allow for more housing while building on their existing transit networks.