At a glance
- The National Center for Health Statistics (NCHS) has developed a system (scheme) for classifying U.S. counties by how urban or rural they are.
- Researchers can use the scheme to study issues like differences in health risk and health status between people living in urban and rural counties.
Overview
The National Center for Health Statistics (NCHS) has developed a six-level urban-rural classification scheme for U.S. counties and other jurisdictions that are the equivalent of counties in their area. NCHS has updated the scheme based on the and information about all people living in each of the counties—its population—taken from Census' 2022 of July 1, 2022. NCHS used these resources to classify U.S. counties and county equivalents into six categories—four metropolitan and two nonmetropolitan.
The NCHS scheme allows researchers, policy makers, and others to study American's health in relation to the urbanization level—more urban or more rural—of the place they live. They also can use NCHS data to monitor the health of people living in urban and rural areas.
2023 Urban-Rural Classification Scheme
The 2023 NCHS Urban-Rural Classification Scheme classifies 3,144 U.S. counties. The counties include county equivalents such as parishes in Louisiana, boroughs in Alaska, and planning regions in Connecticut. They do not include county equivalents in U.S. territories.
Definitions
Metropolitan counties
1. Large central metro counties in metropolitan areas of 1 million population or more that—
- Contain the entire population of the largest principal city of the metropolitan area, or
- Are entirely contained in the largest principal city of the metropolitan area, or
- Contain at least 250,000 residents of any principal city in the metropolitan area
2. Large fringe metro counties in metropolitan areas of 1 million or more population that do not qualify as large central
3. Medium metro counties in metropolitan areas of 250,000 to 999,999 population
4. Small metro counties in metropolitan areas of 50,000 to 249,999 population
Nonmetropolitan counties
5. Micropolitan counties in micropolitan statistical areas
6. Noncore counties that did not qualify as micropolitan
2023 urban-rural levels
The 2023 Urban-Rural Classification Scheme includes 1,186 metropolitan counties and 1,958 nonmetropolitan counties. Although most counties are classified as nonmetropolitan, the majority of the U.S. population lives in metropolitan areas (86%).
| Number of counties | Percent of U.S. resident population (2022) | |
|---|---|---|
| All counties | 3,144 | 100% |
| Metropolitan counties | 1,186 | |
| Large central metro | 67 | 30.8% |
| Large fringe metro | 368 | 25.5% |
| Medium metro | 395 | 21.2% |
| Small metro | 356 | 8.8% |
| Nonmetropolitan counties | 1,958 | |
| Micropolitan | 658 | 8.4% |
| Noncore | 1,300 | 5.4% |
There were minimal differences in county assignments between the 2023 and 2013 schemes. Differences in county assignments are largely due to population changes over time or to counties being added or deleted.
| 2023 scheme | 2013 scheme | |||||
| Number of counties | Percent of counties | Percent of U.S. resident population (2022) | Number of counties | Percent of counties | Percent of U.S. resident population (2012) | |
| All counties | 3,144 | 3,143 | ||||
| Metropolitan counties | 1,186 | 86.2 | 1,167 | 85.2 | ||
| Large central metro | 67 | 2.1 | 30.8 | 68 | 2.2 | 30.5 |
| Large fringe metro | 368 | 11.7 | 25.5 | 368 | 11.7 | 24.7 |
| Medium metro | 395 | 12.6 | 21.2 | 373 | 11.9 | 20.9 |
| Small metro | 356 | 11.3 | 8.8 | 358 | 11.4 | 9.2 |
| Nonmetropolitan counties | 1,958 | 13.8 | 1,976 | 14.8 | ||
| Micropolitan | 658 | 20.9 | 8.4 | 641 | 20.4 | 8.7 |
| Noncore | 1,300 | 41.3 | 5.4 | 1,335 | 42.5 | 6.1 |
Past versions
NCHS first developed its urban-rural scheme in 2001 (referred to as the 1990 census-based scheme). NCHS has updated the scheme in 2006, 2013, and 2023.
The basic framework of the four schemes is the same. NCHS used the same classification rules to assign counties to the six urban-rural categories in the 2023, 2013, and 2006 schemes. Somewhat different classification rules were used for the 1990 census-based scheme. More information is available in the technical and file documentation.
2013 NCHS Urban-Rural Classification Scheme for Counties, based on—
- OMB's
- The of the resident U.S. population
2006 NCHS Urban-Rural Classification Scheme for Counties, based on—
- OMB’s
1990 Census-based NCHS Urban-Rural Classification Scheme for Counties, based on—