Three years ago, we did a study of the 21st century growth of American metropolitan and micropolitan areas by size of the metro and by region of the US. The growth in medium sized metros, which include all the suburbs of a city, has continued since then. The medium places have outpaced the giants where so many American live, though that varies tremendously by location of the giant “megacity.”
We have updated our numbers in this article. We believe this size and region approach may be unique, certainly rare. At the end of this article, we list the fastest growing, slowest growing (shrinking), and largest of the 535 urban areas in this study.
The first conclusion is that the biggest single group in terms of total added population consists of the urban areas which started with a 2000 population of 750,000 to 2,500,000, so neither the giants nor the small towns:
If we look at percentage growth, which tells us more about what the future might look like, we see that metros which started the century between 750,000 and 5 million grew fastest:
Note that the low 16% growth of the giants would be much lower than that without Dallas-Ft. Worth and Houston, the two Texas metros which began the century with over 5 million people. While the 2.5 to 5 million group grew the fastest at 32.6%, in California, Texas, the Midwest, and the Northeast, those metros that started out between 750,000 and 2.5 million grew even faster than their larger neighbors. Those places between 250,000 and 750,000 boomed in the Mountain states and Florida. The smallest metros did especially well out in the mountains and in Florida.
Many factors, including job opportunities, cost of living, weather, tax rates, healthcare, and quality of schools affect American migration habits. All are reflected in these numbers, but we also must wonder if people are looking for an easier lifestyle, shorter commute times, and sometimes lower crime risk that come with smaller metros. The cost-of-living gaps are also often substantial. At the same time, living in a fast-growing area is very different from living in a shrinking or no-growth area; each brings its own challenges.
(Your author grew up in a city of 60,000 and now lives in a metro area of about 250,000, but has lived in New York City, a rural Texas ranching town of 1300 people, Chicago, St. Louis, Dallas, and Austin for more years than any other, thus experiencing a wide range of living and growth environments with their advantages and disadvantages.)
Another way to look at this is by looking at each area and size group’s share of the total American urban population growth:
That shows us the same principal indicated in the other tables: the “action” has been in the Southeast, Texas, Florida, and the Mountain states in that order. Southeastern metros in the middle “C” group outperformed every other group. This data jives with the studies of domestic migration that we have previously done.
After this growth phase, here is the mix of our population in the most recently published data, showing how intensely urban (over 90% out of a total of 340 million) our society is, a big change from 100 years ago:
That mix will continue to change as these long-term trends continue, and as they accelerate or decelerate.
For reference, here are the number of statistical areas in each region and size group:
It is always fun to look at specific metros. These were the fastest growing this century so far; the boom of the larger metros like Austin and Orlando is quite amazing (note that size classes are based on where they started in 2000):
And the slowest growing places, with the slowest at the bottom, showing that despite the overall growth of the Southeast, there are parts of the South that are not growing:
Next, the list of the 50 largest areas by 2024 population (Census Bureau estimates, the latest available); the size classes are based on their 2000 populations. Few big coastal cities outside Florida have grown as fast as the national average of 22.4%:
One more table, the metros that added the most people so far this century:
We should note that these trends took a bend during COVID and in recent years, with the big metros in California and elsewhere slowing down, sometimes shrinking from their population peaks if you exclude the immigrants to those metros from outside the United States. See our prior work.
Note that our data may differ from other published data, as we have tried to use the same geographies for both 2000 and 2024. Some metro definitions (by the Census Bureau) change, adding or subtracting counties, but we have used the current definitions in calculating the historic 2000 numbers.
Those geography lovers among our readers may ask where we categorized Oklahoma, a hard state to place if you make Texas its own region, so we put it in the Southeast. Creating a Texas-Oklahoma region would not change any of the major conclusions. We did not include Puerto Rico in these analyses.
This data is limited to micropolitan, metropolitan, and combined statistical areas and therefore excludes true rural areas, which have not been growth areas overall and represent less than 10% of the US population. Any metropolitan areas that are part of combined statistical areas were only counted in the combined areas, ensuring that no place was counted twice.
The data was compiled with the assistance of ChatGPT 5.4, and we have made every effort to check the data, but it can make mistakes. There are quirks in a complex process like this, such as Louisville ending up in the Midwest region because its metro area extends into Indiana. However, that might make sense: Louisville is perhaps as tightly connected to Indianapolis and Cincinnati as to the more deeply southern (and faster growing) Nashville.
We always welcome your comments or questions, just reply to this email or email us at gary@americanbusinesshistory.org.
If anyone, including researchers and scholars, has questions or would like a copy of our full dataset in Excel form, please contact us.
Gary Hoover
Executive Director
American Business History Center
