County Population Trends, 2010 to 2018

Between 2010 and 2018, the nation's most urban counties grew faster than any other county type, according to the Census Bureau's county population estimates. A Demo Memo analysis of 2010-to-2018 county population trends along the Rural-Urban Continuum documents ongoing metro growth and continuing rural decline. But patterns are changing.

The Rural-Urban Continuum is the federal government's way of classifying counties by their degree of urbanity. The continuum is a scale ranging from 1 (the most urban counties, in metropolitan areas of 1 million or more) to 9 (the most rural counties, lacking any settlements of 2,500 or more people and not adjacent to a metropolitan area). If you sort the nation's 3,000-plus counties by their rank on the continuum, then measure population change between 2010 and 2018 for each rank, this is the result...

County population change 2010-2018 by Rural-Urban Continuum Rank
1. 7.6% for counties in metros with 1 million or more people
2. 6.2% for counties in metros of 250,000 to 1 million people
3. 4.1% for counties in metros with less than 250,000 people
4. 0.5% for nonmetro counties with urban pop of 20,000-plus, adjacent to metro
5. 1.7% for nonmetro counties with urban pop of 20,000-plus, not adjacent to metro
6. –1.0% for nonmetro counties with urban pop of 2,500–19,999, adjacent to metro
7. –1.6% for nonmetro counties with urban pop of 2,500–19,999, not adjacent to metro 
8. –1.0% for nonmetro counties with urban pop less than 2,500, adjacent to metro 
9. –1.9% for nonmetro counties with urban pop less than 2,500, not adjacent to metro 

The long-term pattern has been one of urban growth—the more urban, the greater the growth. But an examination of annual growth rates reveals important changes. Counties with a rank of 1 on the continuum (the most urban) grew faster than any other county type in every year between 2010 and 2017. But between 2017 and 2018, the growth rate of rank 1 counties slipped below that of rank 2 counties—an increase of 0.72 percent for rank 1 counties versus a slightly larger 0.75 percent increase for rank 2 counties. Behind the slower growth of rank 1 counties are small declines between 2017 and 2018 in the populations of the three largest metro areas —New York, Los Angeles, and Chicago. 

Conversely, some nonmetropolitan counties that had been steadily losing population are now making small gains. Rank 6 and 8 counties grew slightly in both 2017 and 2018, but those gains were not large enough to make up for losses earlier in the decade.  

Source: USDA, Economic Research Service, Rural-Urban Continuum Codes and Census Bureau, County Population Totals and Components of Change: 2010–2018