There are many different defitions of rurality, both within research community and in public policy. A recent systematic literature review (Nelson et al. 2021) identified 65 research articles with different rurality definitions. A selection of definitions is presented here. In many cases, non-rural is defined first, and everything outside of it is considered rural. Figure 4 visually compares what apprears to be rural in Wisconsin under different definitions.
Two major definitions which the Federal government uses to identify the rural status of an area are the Census Bureau’s “Urban Area” and the OMB’s “Core-Based Statistical Area”.
The Census Bureau’s urban-rural classification is a delineation of geographic areas, identifying both individual urban areas and the rural areas of the nation. The Census Bureau’s urban areas represent densely developed territory, and encompass residential, commercial, and other non-residential urban land uses. The Census Bureau delineates urban areas after each decennial census by applying specified criteria to decennial census and other data. “Rural” encompasses all population, housing, and territory not included within an urban area.
The U.S. Census Bureau identifies two types of urban areas: Urbanized Areas (UAs) of 50,000 or more people and Urban Clusters (UCs) of at least 2,S00 and less than 50,000 people. Urban Areas are not defined in terms of any other standard spatial unit. The borders of an urban area are defined by the density of commuting patterns in the orbit of urban cores of various population size.
Data source page: TIGER/Line® Shapefiles. Boundaries are defined after decennial census. Using latest national data files for every revision: 2009 file for 2000 boundaries, 2021 file for 2010 boundaries. This may be worth examining more closely. OMB metro delineations are updated after decennials AND annually from ACS. Maybe urban area shapes change between decennials too.
Processed geodataframe columns:
UACE: Urban area code.NAME: Urban area name.UATYP: Urban area type. "U" - Urbanized Area, "C" - Urban Cluster.ALAND, AWATER: land and water area (square meters).INTPTLAT, INTPTLON: Latitude and longitude of the internal point.geometry: Geopandas (multi)polygons.Urban area names are typically "city_name, state_postal_abbreviation" ("Madison, WI", "Hartford, CT"). But bigger aglomeration names might include multiple cities ("Los Angeles--Long Beach--Anaheim, CA") and lie in multiple states ("Kansas City, MO--KS", "Minneapolis--St. Paul, MN--WI", "New York--Newark, NY--NJ--CT").
Loading from parquet file.| UACE | NAME | UATYP | ALAND | AWATER | INTPTLAT | INTPTLON |
|---|---|---|---|---|---|---|
| 08434 | Bloomsburg--Berwick, PA | U | 84705392 | 3059507 | 41.016958 | -76.412130 |
| 51445 | Los Angeles--Long Beach--Anaheim, CA | U | 4503972988 | 54854584 | 33.982667 | -118.104332 |
| 09730 | Brawley, CA | C | 20529228 | 0 | 32.977987 | -115.531845 |
Figure 1 shows how urban areas expand in Dane county, Wisconsin between 2000 and 2010 censuses. Small 2000 urban clusters of Cross Plains and DeForest by 2010 merged with bigger Madion urbanized area.
Loading from parquet file.
Loading from parquet file.One of the most widely used definitions of rural is everything outside of metropolitan areas. Counties outside of metro/micro areas are sometimes called “noncore”.
Metropolitan definition takes counties as base unit and classifies them using data on urban area residents and commuting flows.
The 2010 standards provide that each CBSA must contain at least one urban area of 10,000 or more population. Each metropolitan statistical area must have at least one urbanized area of 50,000 or more inhabitants. Each micropolitan statistical area must have at least one urban cluster of at least 10,000 but less than 50,000 population.
Under the standards, the county (or counties) in which at least 50 percent of the population resides within urban areas of 10,000 or more population, or that contain at least 5,000 people residing within a single urban area of 10,000 or more population, is identified as a “central county” (counties). Additional “outlying counties” are included in the CBSA if they meet specified requirements of commuting to or from the central counties.
A metropolitan or micropolitan statistical area’s geographic composition, or list of geographic components at a particular point in time, is referred to as its “delineation.”
Multiple sets of delineation files exist:
Number of counties in CBSA tables
| 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2013 | 2015 | 2017 | 2018 | 2020 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| metro | 1158 | 1158 | 1158 | 1160 | 1160 | 1168 | 1168 | 1236 | 1236 | 1238 | 1251 | 1251 |
| micro | 695 | 697 | 699 | 698 | 699 | 692 | 694 | 646 | 663 | 661 | 664 | 665 |
| all | 1853 | 1855 | 1857 | 1858 | 1859 | 1860 | 1862 | 1882 | 1899 | 1899 | 1915 | 1916 |
| 2007 | 2008 | 2009 | 2013 | 2015 | 2017 | 2018 | 2020 | ||
|---|---|---|---|---|---|---|---|---|---|
| METRO_MICRO | CENTRAL_OUTLYING | ||||||||
| metro | central | 727 | 731 | 732 | 785 | 785 | 786 | 792 | 792 |
| outlying | 433 | 437 | 436 | 451 | 451 | 452 | 459 | 459 | |
| micro | central | 596 | 593 | 595 | 554 | 569 | 568 | 559 | 560 |
| outlying | 103 | 99 | 99 | 92 | 94 | 93 | 105 | 105 |
Boundary shapefiles, both TIGER (high res) and catrographic (low res) are available from Census Bureau geography program.
| 2010 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | |
|---|---|---|---|---|---|---|---|---|---|---|
| GEO_ID | X | |||||||||
| CBSA | X | |||||||||
| NAME | X | X | X | X | X | X | X | X | X | X |
| LSAD | X | X | X | X | X | X | X | X | X | X |
| CENSUSAREA | X | |||||||||
| geometry | X | X | X | X | X | X | X | X | X | X |
| CSAFP | X | X | X | X | X | X | X | X | X | |
| CBSAFP | X | X | X | X | X | X | X | X | X | |
| AFFGEOID | X | X | X | X | X | X | X | X | X | |
| GEOID | X | X | X | X | X | X | X | X | X | |
| ALAND | X | X | X | X | X | X | X | X | X | |
| AWATER | X | X | X | X | X | X | X | X | X | |
| NAMELSAD | X | X |
Before 2010 there is a column CENSUSAREA - “Area of entity before generalization in square miles”. After 2010 there are ALAND and AWATER. For most entries CENSUSAREA equals ALAND after conversion from square miles to square meters, but not always.
| 2010 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | |
|---|---|---|---|---|---|---|---|---|---|---|
| micro | 581 | 541 | 541 | 541 | 556 | 556 | 555 | 546 | 547 | 547 |
| metro | 374 | 388 | 388 | 388 | 389 | 389 | 390 | 392 | 392 | 392 |
| all | 955 | 929 | 929 | 929 | 945 | 945 | 945 | 938 | 939 | 939 |
The ERS’s three measures of urban influence and spatial effect are the Urban Influence codes, the Urban-Rural Continuum codes, and the Urban-Rural Commuting Area codes.
Each set of codes classifies corresponding spatial units into multiple groups, leaving decision to draw the line between rural and non-rural to the researcher. The unit of analysis for the Urban Influence codes and the Rural-Urban Continuum codes is the county. For the Rural-Urban Commuting Area codes the unit of analysis is the census tract.
Preparation of ERS codes is done in a separate notebook.
Sub-county division used by RUCA classification allows to identify parts of metro counties that are not strongly connected to respective urban areas. Likewise, there are parts of non-metro counties that are highly connected to an adjacent metro county, but are not big enough to make the entire county qualify for metro criteria.
Rural areas, derived from RUCA codes, often cross CBSA-based rural boundaries, as can be visually seen in Figure 4.
| RUCA_CODE | RUCA_SHORT | RUCA_DESC |
|---|---|---|
| 1 | metro core | Metropolitan area core: primary flow within an urbanized area (UA) |
| 2 | metro high comm | Metropolitan area high commuting: primary flow 30% or more to a UA |
| 3 | metro low comm | Metropolitan area low commuting: primary flow 10% to 30% to a UA |
| 4 | micro core | Micropolitan area core: primary flow within an Urban Cluster of 10,000 to 49,999 (large UC) |
| 5 | micro high comm | Micropolitan high commuting: primary flow 30% or more to a large UC |
| 6 | micro low comm | Micropolitan low commuting: primary flow 10% to 30% to a large UC |
| 7 | UC core | Small town core: primary flow within an Urban Cluster of 2,500 to 9,999 (small UC) |
| 8 | UC high comm | Small town high commuting: primary flow 30% or more to a small UC |
| 9 | UC low comm | Small town low commuting: primary flow 10% to 30% to a small UC |
| 10 | rural | Rural areas: primary flow to a tract outside a UA or UC |
| 99 | NA | Not coded: Census tract has zero population and no rural-urban identifier information |
This definition of rurality is based on tracts and uses OMB and RUCA definitions with additional refinements in large metro tracts.
HRSA refers to the Health Resources and Services Administration. It is particularly its sub-unit, the Federal Office of Rural Health Policy (FORHP), that is responsible for this definition of rurality. For its own administrative purposes it considers a census tract to be rural if it is contained within a county that is not part of a CBSA.
Quote from HRSA page.
We define the following areas as rural: - All non-metro counties - All metro census tracts with RUCA codes 4-10 and - Large area Metro census tracts of at least 400 sq. miles in area with population density of 35 or less per sq. mile with RUCA codes 2-3. In larger tracts, you cannot use RUCA codes alone. The codes do not factor in distance to services and low numbers of people. - Beginning with Fiscal Year 2022 Rural Health Grants, we consider all outlying metro counties without a UA to be rural.
Lists of rural areas by county, census tract, and ZIP code are available on HRSA Data Files page.
There is an obvious family resemblance between “remote” and “rural” which might find some analytical use.
To assist in providing policy-relevant information about conditions in sparsely-settled, remote areas of the U.S. to public officials, researchers, and the general public, ERS has developed ZIP-code-level frontier and remote area (FAR) codes.
The term “frontier and remote” is used here to describe territory characterized by some combination of low population size and high geographic remoteness. FAR areas are defined in relation to the time it takes to travel by car to the edges of nearby Urban Areas (UAs). Four levels are necessary because rural areas experience degrees of remoteness at higher or lower population levels that affect access to different types of goods and services. A relatively large number of people live far from cities providing “high order” goods and services, such as advanced medical procedures, stores selling major household appliances, regional airport hubs, or professional sports franchises. Level one FAR codes are meant to approximate this degree of remoteness. A much smaller, but still significant, number of people find it hard to access “low order” goods and services, such as grocery stores, gas stations, and basic health-care services. Level four FAR codes more closely coincide with this much higher degree of remoteness. Other types of goods and services—clothing stores, car dealerships, movie theaters—fall somewhere in between. Users are able to choose the definition that bests suits their specific needs.
Two revisions of the codes currently exist, based on population data from 2000 and 2010 censuses. 2000 revision does not use road network travel time.
Although data is provided at ZIP code level, Census Bureau ZCTAs are not an exactly appropriate spatial unit. Explanation from 2010 data spreadsheet:
ZIP Code areas used here come from ESRI mapping data, based on 2014 information from the U.S. Postal Service. These codes may or may not match exactly with other ZIP Code data sources due to frequent changes in ZIP Code configurations. They do not fully match with the Census Bureau’s ZIP Code Tabulation Areas (ZCTAs). For more information, see Methodology Statement: 2013/2018 ESRI US Demographic Updates, August 2013: link.
Dataframes contain all columns from the source spreadsheets and additional variable FAR_LEVEL.
| Variable | Description |
|---|---|
| ZIP | 5-digit ZIP Code |
| STATE | State postal abbreviation |
| NAME | ZIP Code area name (2010 only) |
| FAR1 | FAR classification, level one: 0=not FAR, 1=FAR |
| FAR2 | FAR classification, level two: 0=not FAR, 1=FAR |
| FAR3 | FAR classification, level three: 0=not FAR, 1=FAR |
| FAR4 | FAR classification, level four: 0=not FAR, 1=FAR |
| GRIDPOP | ZIP code population estimate |
| SQMI | ZIP code land area in square miles |
| DENSITY | ZIP code population per square mile |
| FR1POP | ZIP code population classified as FAR level one |
| FR2POP | ZIP code population classified as FAR level two |
| FR3POP | ZIP code population classified as FAR level three |
| FR4POP | ZIP code population classified as FAR level four |
| FR1PCT | Percent of ZIP code population classified as FAR level one |
| FR2PCT | Percent of ZIP code population classified as FAR level two |
| FR3PCT | Percent of ZIP code population classified as FAR level three |
| FR4PCT | Percent of ZIP code population classified as FAR level four |
| FAR_LEVEL | Highest FAR level, between 0 and 4 |
2010 tables are de-duplicated. There are five ZIP duplicates still remain that cross state boundaries: 57724 (MT, SD), 73949 (OK, TX), 63673 (MO, IL), 42223 (TN, KY), 72395 (AR, TN). These records are equal in every column except for STATE.
No ZIP duplicates exist in 2000 table.
| ZIP | STATE | NAME | FAR1 | FAR2 | FAR3 | FAR4 | GRIDPOP | SQMI | DENSITY | FR1POP | FR2POP | FR3POP | FR4POP | FR1PCT | FR2PCT | FR3PCT | FR4PCT | FAR_LEVEL | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 18393 | 38680 | MS | Walls | 0 | 0 | 0 | 0 | 7496.772254 | 28.99 | 258.598560 | 1.761979 | 1.761979 | 1.761979 | 1.761979 | 0.023503 | 0.023503 | 0.023503 | 0.023503 | 0 |
| 14145 | 50575 | IA | Pomeroy | 1 | 0 | 0 | 0 | 918.779790 | 46.71 | 19.669873 | 918.779790 | 7.530852 | 7.530852 | 7.530852 | 100.000000 | 0.819658 | 0.819658 | 0.819658 | 1 |
| 28558 | 00179 | NH | Chandlers Purchase | 1 | 1 | 0 | 0 | 1.117135 | 2.13 | 0.524477 | 1.117135 | 1.117135 | 0.000000 | 0.000000 | 100.000000 | 100.000000 | 0.000000 | 0.000000 | 2 |
| 15209 | 41776 | KY | Wooton | 1 | 1 | 1 | 0 | 1735.900326 | 41.84 | 41.489014 | 1735.900326 | 1735.900326 | 1735.900326 | 838.158842 | 100.000000 | 100.000000 | 100.000000 | 48.283812 | 3 |
| 7450 | 36921 | AL | Toxey | 1 | 1 | 1 | 1 | 1201.331922 | 100.88 | 11.908524 | 1201.331922 | 1083.740341 | 1083.740341 | 1083.740341 | 100.000000 | 90.211566 | 90.211566 | 90.211566 | 4 |
FAR ZIP areas in Wisconsin part of Duluth metro area, WI. Note: Census Bureau ZCTAs are used as shapes instead of ESRI.
UA
Rural is everyting outside of urbanized areas and urban clusters. High resolution source shapes are simplified to reduce HTML size for online publication.
CBSA
Rural = everything outside of metropolitan counties. Micropolitan areas are by this definition also rural.
RUCA
Rural = micro and non-core codes (4, 5, 6, 7, 8, 9, 10, 99). Tract shapes are simplified.
FAR
Compared to other definition, Frontier and Remote is rather conservative. Many areas that are not FAR (level 0) are classified as rural by other definitions. So we apply the most aggressive criterion and classify areas with any level of FAR (1, 2, 3 or 4) as rural.
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