Rural-Urban Commuting Area (RUCA) codes

What are Rural-Urban Commuting Area (RUCA) codes?

RUCA codes are a census tract-based classification that uses standard census measures of population density, levels of urbanization and journey-to-work commuting to characterize all U.S. census tracts with respect to their rural/urban status and commuting relationships to other census tracts. There is also a ZIP code version of the RUCA codes that approximates the census tract version.

In the RUCA classification, each tract (or ZIP code) is assigned a primary code between 1 and 10 depending on metropolitan/micropolitan/small town/rural characteristics and basic commuting flows. Tracts (or ZIP codes) are also assigned a secondary code based on secondary commuting flows. Using RUCA codes, census tracts (and ZIP codes) can be usefully grouped in multiple ways to facilitate geographical analysis at many levels.

The current versions of the RUCA codes are based on the 2010 decennial census and the 2006-2010 American Community Survey.

RUCA codes were developed collaboratively by the following:

  • Federal Office of Rural Health Policy (FORHP)
  • U.S. Department of Agriculture’s Economic Research Service (ERS)
  • WWAMI Rural Health Research Center (WWAMI RHRC), funded by FORHP and ERS

The principal developers were Richard Morrill, PhD (WWAMI RHRC), John Cromartie, PhD (ERS) and Gary Hart, PhD (WWAMI RHRC).

The concept of rural is complex, multifaceted, and often, vague. In addition, limitations on data availability and the use of different areal units (e.g., counties, census tracts, ZIP code areas, blocks) can create further confusion and disagreement about what kinds of places should be considered “rural.” Because the concept of rural is multidimensional and definitions are tied often to specific views and tasks, no one definition of rural can satisfy all users and purposes. For public policy and research purposes, the definition of rural being applied should be clearly identified and justified. For most public policy purposes, definitions should meet certain criteria, such as being systematic and objective. During the mid-1990s, substantial interest developed among staff at the USDA Economic Research Service (ERS), the Census Bureau, HRSA’s Federal Office of Rural Health Policy (FORHP), and academic demographers and geographers in developing sub-county measures of rural/urban status that would meet those criteria. Those discussions led to a WWAMI RHRC project funded by the FORHP and the ERS that developed the first version of the RUCA codes.

The RUCA codes were designed to provide a definition of rural and urban based on the Census Bureau’s carefully constructed definitions of urbanized areas and urban clusters, which are based on complex criteria including population density and population work commuting patterns. The RUCA taxonomy is based on the size of cities and towns and their functional relationships as measured by work commuting flows. This approach supports the use of the RUCA codes in a wide variety of analytic contexts. The 21 separate codes in the current version (there were originally 33 codes) of the RUCA codes allow demographers, health care researchers, policy makers, and others to aggregate the codes according to their needs. The large number of different codes allows great flexibility in these aggregations. For example, RUCA codes can be used to target a federal health care program to the most appropriate subpopulation. Because the codes are based on census tracts, they are geographically more specific than larger county-based definitions and avoid the problems associated with the heterogeneity of these large units (i.e., problems of under and over bounding the actual boundaries of cities and towns). To make the codes more useful for health care applications, a ZIP code version of the RUCA codes was developed. Older versions of the ZIP code RUCA codes are available on this website and the current version is available from the ERS.

Key References

Hart LG, Larson EH, Lishner, DM. Rural definitions for health policy and research. Am J Public Health. 2005;95(7):1149-1155. Link to Pub Med.

Morrill R, Cromartie J, Hart LG. Metropolitan, urban, and rural commuting areas: toward a better depiction of the U.S. settlement system. Urban Geog. 1999;20(8):727-748.


The development of the RUCA codes was supported by HRSA’s Federal Office of Rural Health Policy (FORHP) and the USDA’s Economic Research Service (ERS). The project was led by Drs. Gary Hart (WWAMI RHRC-University of Washington), John Cromartie (ERS) and Richard Morrill (Department of Geography-University of Washington).

Where can CURRENT versions of RUCA codes be obtained?

Current versions of the census tract and ZIP code RUCA codes based on 2010 census data Available for download from the U.S. Department of Agriculture Economic Research Service website:
Census tract RUCA codes based on 1990 and 2000 census data U.S. Department of Agriculture Economic Research Service website ( has links to the 1990 and 2000 census tract RUCA code files.
Users are cautioned that methodological changes to both the census tract and the RUCA classification scheme may impair comparability of analyses based on different versions of the RUCA codes.

Where can earlier versions of ZIP code RUCA codes be obtained?

Three versions of the ZIP code RUCA codes are available on this site:

Version 1.1 The first publicly released version of the ZIP code RUCA codes. It is based on 1998 ZIP code areas and 1990 census commuting data.
Version 2.0(a) Based on 2004 ZIP code areas and 2000 census commuting data.
Version 2.0(b) An update of Version 2.0(a), based on 2006 ZIP code areas and 2000 census commuting data.