Big-City Counties Growing the Fastest (Still)

The nation's most urban counties continue to grow faster than any other county type according to the Census Bureau's 2015 county population estimates. A Demo Memo analysis of 2010-to-2015 county population trends along the Rural-Urban Continuum documents strong metro growth (the bigger, the better) and continuing rural decline.

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 2015 for each rank, this is the result...

County population change 2010-2015 by Rural-Urban Continuum Rank
1. 5.3% for rank 1 counties, in metros with 1 million or more people
2. 3.9% for rank 2 counties, in metros of 250,000 to 1 million people
3. 2.6% for rank 3 counties, in metros with less than 250,000 people
4. 0.1% for rank 4 counties, nonmetro adjacent to metro with urban pop of 20,000+
5. 1.7% for rank 5 counties, nonmetro not adjacent to metro with urban pop of 20,000+
6. -0.8% for rank 6 counties, nonmetro adjacent to metro with urban pop of 2,500-19,999
7. -0.5% for rank 7 counties, nonmetro not adjacent to metro with urban pop of 2,500-19,999
8. -1.1% for rank 8 counties, nonmetro adjacent to metro with urban pop less than 2,500
9. -1.2% for rank 9 counties, nonmetro not adjacent to metro, urban pop less than 2,500

The most urban counties (a 1 on the scale) grew the fastest between 2010 and 2015. The most rural counties (8 and 9 on the scale) experienced the biggest declines. A look at annual rates of population change by Rural-Urban Continuum shows declines in every year between 2010 and 2015 for counties ranking 6, 7, 8, and 9 on the continuum. Counties with a rank of 1 on the continuum grew by more than 1 percent in every year. 

Source: USDA, Economic Research Service, Rural-Urban Continuum Codes and Census Bureau, Population Estimates, County Total: Vintage 2015