MAFES Publications and Scholarship

The Index of Relative Rurality (IRR): US County Data for 2020



The Index of Relative Rurality (IRR) is a continuous, threshold-free, and unit-free measure of rurality.

The original version of the IRR was proposed by Waldorf (2006, as an alternative to the traditional discrete threshold-based classifications, such as the Rural-urban Continuum Code and the Urban Influence Code. Waldorf and Kim (2015) re-designed measuring the index and applied it to publish improved county-level IRR for 2000 and 2010. IRR 2020 was measured by the same method suggested in 2015 except for the network data (North American Roads*) due to the data availability. (* Bureau of Transportation Statistics (BTS),

The IRR has three significant advantages over typology-based rurality measures. (1) It is spatially flexible in that it can be designed for any spatial units; (2) it is a relative measure and thus embeds rurality in the broader system of settlements; (3) it is analytically more easily handled than threshold-based typologies.

The IRR ranges between 0 (low level of rurality, i.e., urban) and 1 (most rural). Four steps are involved in its design:

1. Identifying the dimensions of rurality: population size, density, remoteness, and built-up area.
2. Selecting measurable variables to adequately represent each dimension:
a. Size: logarithm of population size
b. Density: logarithm of population density.
c. Remoteness: network distance.
d. Built-up area: urban area (as defined by the US Census Bureau) as a percentage of total land area.
3. Re-scaling the variables onto bounded scales that range from 0 to 1.
4. Selecting a link function: unweighted average of the four re-scaled variables.


For more information:
Waldorf, Brigitte, and Ayoung Kim. 2015. "Defining and Measuring Rurality in the US: From Typologies to Continuous Indices." Commissioned paper prepared for the National Academies of Sciences Workshop on Rationalizing Rural Classifications, April 2015, Washington, DC.



Publication Date


Spatial Coverage

County level, US


College of Agriculture and Life Sciences


Department of Agricultural Economics

Research Center

Mississippi Agricultural and Forestry Experiment Station


IRR, Index of Relative Rurality


Agricultural and Resource Economics | Place and Environment | Regional Economics | Rural Sociology