Big-City Counties Still Fastest Growing, but...

The nation's most urban counties continue to grow faster than any other county type according to the Census Bureau's 2017 county population estimates. A Demo Memo analysis of 2010-to-2017 county population trends along the Rural-Urban Continuum documents ongoing metro growth (the bigger, the better) and continuing rural decline. But the 2017 data reveal changing patterns of growth.

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 2017 for each rank, this is the result...

County population change 2010-2017 by Rural-Urban Continuum Rank
1. 7.1% for counties in metros with 1 million or more people
2. 5.5% for counties in metros of 250,000 to 1 million people
3. 3.5% for counties in metros with less than 250,000 people
4. 0.3% for nonmetro counties with urban pop of 20,000-plus, adjacent to metro
5. 1.6% 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. –1.4% for nonmetro counties with urban pop of 2,500–19,999, not adjacent to metro 
8. –1.3% for nonmetro counties with urban pop less than 2,500, adjacent to metro 
9. –1.7% for nonmetro counties with urban pop less than 2,500, not adjacent to metro 

Counties with a rank of 1 on the continuum (the most urban) have grown faster than any other county type in every year since 2010. But the pattern of growth is changing as the decade progresses. Average annual growth rates in smaller metro counties (rank 2 and 3) are increasing, while average annual growth is slowing in the largest urban counties. Some nonmetro counties saw their population losses turn to small gains in 2017 (rank 6 and 8). These emerging trends are signs that the economic recovery is increasingly widespread.  

Source: USDA, Economic Research Service, Rural-Urban Continuum Codes and Census Bureau, County Population Totals and Components of Change: 2010–2017