# Geographic Areas Reference Manual/Chapter 6

Chapter 6
Users of Census Bureau data find it advantageous to relate these data to geographic entities that represent major sections of the United States. These geographic regions usually comprise combinations of States or counties. Such groupings are particularly appropriate for a large nation such as the United States, with its diverse physical and cultural geography, and its numerous State and county components.
This chapter discusses the Census Bureau’s system of State groupings, the Census Bureau’s regions and divisions, as well as other combinations based on groupings of contiguous counties. Figure 6-1 shows the Census Bureau’s current two-level system for the regional subdivision of the United States. Each of the current nine census divisions consists of several States (including the District of Columbia, located in the South Atlantic Division); each of the four current census regions consists of two or three divisions (the Midwest Region was designated as the North Central Region until June 1984). At both the region and division level, the framework of areas provides complete coverage of the entire Nation. The purpose of this framework is to provide large units that are roughly similar in terms of historical development, population characteristics, economy, and the like. As a result, the regions and divisions serve not only to summarize data for the same groups of States over a long period of time, but also to provide a larger geographic framework for comparative statistical analysis.
The current regions and divisions have been standard data tabulation units in almost all Census Bureau tabulation and publication programs since the early 1900s. They appear in many summary tables of the decennial censuses of population and housing, in the publications of the economic and agriculture censuses, and in other statistical presentations, not only those of the Census Bureau, but also of other Federal agencies and private groups. The Census Bureau has no official summary units, other than the regions and divisions, that combine all the Nation’s counties and statistically equivalent entities into a more concise set of general-purpose areas.
​Figure 6-1. Census Regions and Divisions of the United States
The recognition of geographic regions goes back to the colonial period of American history. By the 18th century, the names New England, the Middle Colonies, and the South had come to refer to major sections of the Atlantic seaboard. Each of these regions encompassed several adjacent colonies or areas of settlement. The regional designations reflected particularities of location, climate, topography, economic systems, ethnic composition of the settlers, and systems of local government. One early use of these areas in a statistical compilation dates from before the American Revolution, when the British Government grouped the North American colonies into major colonial regions to summarize foreign trade information. These regions were New England, Middle Colonies, Upper South, and Lower South.
These colonial groupings were the forerunners of the State combinations that appear in the census publications. In fact, the area called New England in colonial times has maintained its geographic identity to the present day. Much the same is true of the Middle Colonies; except for Delaware, which is now in the Census Bureau’s South Atlantic Division, New Jersey, New York, and Pennsylvania remain the component States of the Middle Atlantic Division. (Maryland and Virginia constituted the Upper South; North Carolina, South Carolina, and Georgia, the Lower South.) On a smaller scale, there were other regional designations that appeared in the geographic structure of later censuses; names such as tidewater, coastal plain, piedmont, and the back country were known and in general use even before the American Revolution. These groupings were of interest from the standpoint of statistical presentations because they referred to relatively homogeneous subareas within several colonies (or States). Such geographic subdivisions appeared in several U.S. publications, often as county groupings that represented areas having similar physical and socioeconomic characteristics.
Although 13 States were in place by the time of the first U.S. census in 1790, they were treated as judicial districts in census publications and ​for purposes of data collection. The published data made no use of State combinations. Instead, the summary table listed the 13 States (Connecticut, Delaware, Georgia, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, South Carolina, and Virginia) and three districts (Kentucky, Maine, and Vermont) under one heading, “Districts.” Two territories (Territory Northwest of River Ohio, and Territory South of River Ohio) also were under the heading of “Districts” but below the grand totals for the 16 areas listed above.
In 1790, U. S. marshals conducted the decennial census within judicial districts (this method of enumeration continued until 1870) while Territory South of River Ohio was enumerated by the Governor. Indian warfare prevented the 1790 enumeration of Territory Northwest of River Ohio. Figure 6-2 shows the major geographic entities of the first U.S. Census.
With one exception, the published returns of the 1790 census did not use any geographic combinations of counties within States; the listing of counties within States was alphabetical, with minor civil divisions and some incorporated places appearing in similar sequence. The table for Maryland was the exception; it arranged the county totals by western shore and eastern shore. Although the geographic pattern of the States and territories shifted frequently over the next half-century, decennial census publications from 1800 to 1840 made no use of large-area summary units. In general, States were listed in geographic order, beginning with Maine.
| The United States in 1790 | 13 States |
| The United States in 1790 | 3 Individual Districts (Kentucky, Maine, and Vermont) |
| The United States in 1790 | 2 Territories |
reports. One volume, a compendium, is of particular interest because it was the first pocket-size Census Bureau publication; it contained an extensive explanatory text together with a series of summary tables. The volume introduced several kinds of large-area geographic regions, for which it presented an extensive array of socioeconomic information.
The compendium also featured the first map to appear in a Census Bureau publication. This map showed the area of the conterminous United States subdivided into major slopes, or drainage basins. The interest in drainage basins appears to have had an economic basis. Navigable rivers, canals, and ​overland railways were important elements in the Nation’s transportation and communication systems; the network of canals and railroads existing at the time, along with the plans for expansion of these networks, depended on drainage and topography as well as the population settlement pattern. This map and the several geographic divisions in the accompanying table served as the framework for summarizing the population totals from the first seven decennial censuses. This was the first time that a decennial census publication depicted large-area regions that combined entire States and territories (or portions of them) into summary units.
This publication is significant in that numerous statistical tables are presented using the five great divisions, the first set of standard geographic groupings to appear in a U.S. census publication. Some divisions consisted of several States, others of several States and territories. A more significant fact is that some of the divisions are quite similar to the current census divisions. New England still encompasses the same six States. With the exception of Delaware, the District of Columbia, and Maryland, the Middle States of 1850 correspond to the present Middle Atlantic Division. With the addition of these same three areas, today’s South Atlantic Division corresponds to the 1850 Southern Division (see Figure 6-3).
Although the 1850 compendium made extensive use of the five great divisions, DeBow was not satisfied, because Kentucky and Missouri were separated from Tennessee and Arkansas and included with the Northwestern Division associated with California, Oregon, and the other territories. In search of a better set of areas, DeBow devised a new geographic arrangement for future use. This classification divided the country into three great sections: (1) the Eastern on the Atlantic Coast; (2) the Western on the Pacific Coast; and (3) the Interior, encompassing the States of Alabama, Arkansas, Illinois, Indiana, Iowa, Kentucky, Louisiana, Michigan, Mississippi, Missouri, Ohio, Tennessee, Texas, Wisconsin; the territories of Kansas, Minnesota, Nebraska; and the Unorganized Territory of Oklahoma (see Figure 6-3).
​Figure 6-3. The 1850 Groupings and DeBow’s Suggested Rearrangement
The Five Great Divisions of the 1850 Census Compendium (1850 Areas/Boundaries)
Three Great Sections Proposed for Census Use by DeBow (1854 Areas/Boundaries)
In many respects, DeBow’s great sections and divisions anticipated the present arrangement of census regions and divisions (see Figure 6-1). The Northern Division of the Eastern Section is today’s Northeast Region, the Southern Division of the Eastern Section comprises the present South Atlantic Division, the Southern Interior corresponds largely to today’s East and West South Central Divisions, the Northern Interior resembles the Midwest Region, and the name Western Section still applies to much the same area now referred to as the West.
Other tables (and consequently maps) from the 1850 and 1860 censuses arranged the States differently than the 1850 compendium. Map A in Figure 6-4 depicts the arrangement of States into sections or groups according to geographical situation, production, climate, the pursuits of the inhabitants, and other prominent characteristics. Texas, the Central Slave States, and the Coast Planting States approximated the South. These three sections corresponded to DeBow’s Southeast and Southern Interior, excluding the District of Columbia, Delaware, and Maryland. Some aspects of the sections or groups presented a rather unusual arrangement; for instance, the Middle States of the Atlantic seaboard also included Ohio, and the designation Northwestern States (often including all the territories) appears to be somewhat lacking in geographic precision. On an overall basis, the arrangement probably proved less versatile than the five divisions of the 1860 census. It appeared only once in the 1850 publication, and was featured in one historical table in the 1860 summary volume.
​The summary tables in the 1860 census publication presented a different approach to large-area combinations. Map B in Figure 6-4 shows the standard grouping as a general-purpose arrangement into five divisions, which appeared in a number of statistical tables on agriculture and manufacturing. Two of the divisions, New England and the Middle States, were identical to the official Great Divisions of 1850 (see Figure 6-3). One innovation of this publication was the use of the word Western (in the Western Division) instead of Northwest to designate the interior part of the Nation; another was the name Pacific, appearing for the first time to designate a combination of States.
Another grouping of States (Map C in Figure 6-4) appeared in a specialized table of railroad mileage and costs. This arrangement made some changes to the framework of the five 1860 divisions. It combined Arkansas, Kentucky, and Tennessee into Interior South; it retitled much of the Western Division as Interior North; and it subdivided the remainder of the Southern Division into Southern Atlantic and Gulf. New England and the Middle Divisions did not change.
The 1850 and 1860 censuses involved a general enumeration of annual deaths; the compilations appeared in several tables of mortality statistics that featured various kinds of large-area summary units. One table on mortality statistics used seven natural divisions for comparing 1850 and 1860 information. This approach summarized information on the basis of the physical aspects of the country (see Table 6-1). The geographic coverage is selective and includes only part of the Nation. Some categories represent groups of entire States (Pacific Coast, Northeastern, and Northwestern States), while others refer to groups of counties or parts of States. This regional categorization reflected a continuation of DeBow’s attempts to divide the Nation into natural regions, albeit from a different perspective. The use of counties as building blocks cumulating to larger geographic areas foreshadowed later efforts in statistical and map presentations in the 1870, 1880, 1890, and 1900 censuses.
A. Groupings for Land Area, Population, and Density Table (1850/1860)
B. Five Divisions Used in Many Summary Tables (1860)
C. Areas for Summarizing Railroad Mileage and Costs (1860)
Source: Preliminary Report on the Eighth Census, 1862.
​Table 6-1. Great Natural Divisions for Summarizing Mortality Statistics From the 1850 and 1860 Censuses
| Northeastern States | Maine, New Hampshire, and Vermont |
| Lowlands of the Atlantic Coast | Comprising a general breadth of two counties along the Atlantic from Delaware to Florida, inclusive |
| Intermediate Region | Surrounding the Alleghenies, and extending to the lowlands of the Atlantic and to the Mississippi Valley |
| Allegheny Region | From Pennsylvania, through Virginia and eastern Tennessee to northern Alabama |
| Lower Mississippi Valley | Comprising Louisiana and a breadth of two counties along each bank of the river northward to Cape Girardeau in Missouri |
| Northwestern States | Wisconsin, Iowa, and Minnesota |
| Pacific Coast | California, Oregon, and Washington |
Contrasted with the 1850 and 1860 census reports, the 1870 census publication tables showed scarcely any further development or use of State groupings. The agriculture volume included one table showing the distribution of sheep and wool. Although it grouped States geographically, this table did not provide titles for the various groupings. By 1880, except for the consolidation of Oklahoma and the division of the Dakota Territory into North and South, the boundaries and areas of States and territories in the contiguous 48 States resembled those of today.
Henry Gannett, Geographer of the Census Office during the 1880s, presented a plan for grouping States into larger summary units. Gannett divided the country primarily into three great divisions: the Atlantic, the Great Valley, and the Western, which corresponded to the three primary topographical divisions of the country. The two eastern divisions were divided by a line running approximately east and west. The line between the two sections of the Atlantic Division followed Mason’s and Dixon’s line; the line between the two sections of the Great Valley followed the ​Ohio River and the southern boundary of Missouri. The east–west line separated districts that were very sharply distinguished from one another by population, social conditions, and interests, as well as climate.
In large part, Gannett’s proposal restated the 1850 formulations. His Great Valley of the Mississippi corresponds to DeBow’s interior, central, or middle group of States. Gannett’s arrangement evolved into today’s system of groupings, and pointed toward the present system in that it presented a two-tiered approach: five major geographic divisions, counterparts of today’s census regions, and eleven minor geographic divisions; many of the latter correspond to the current groupings of States into census divisions. For instance, Southern North Atlantic is now the Middle Atlantic Division; together with New England, it now comprises the Northeast Region (instead of the North Atlantic Region). The two minor divisions, Northern South Atlantic (the Upper South of colonial times) and Southern South Atlantic, later merged into the South Atlantic Division of today. A later combination grouped the Rocky Mountain and the Basin and Plateau States into the Mountain Division. Table 6-2 lists Gannett’s 1900 arrangement and shows how it evolved into the present system of groupings.
The summary statistics for the 1880 census of agriculture made use of the five major divisions mentioned above. The 1890 and 1900 publications extended the practice to include data on land area and demographic items, such as the geographical distribution of counties and minor civil divisions, as well as city, urban, and rural populations. The introductory text of one 1890 census report considered this fivefold combination as a natural grouping that brought out many characteristic features of the Nation’s different sections. Among these features were economic specialization, the evolution of population concentrations in cities, and the stage of progress. It described the North Atlantic as the manufacturing section, and designated agriculture as the predominant industry of the North Central States. It further characterized the South Atlantic and South Central States as almost entirely agricultural, in contrast to the West, for which the leading industries were agriculture, mining, and grazing. Such perceptions doubtlessly ​became fixed in the public’s mind, and served to perpetuate the use of this set of standard groupings in the Census Bureau’s publications.
The 1883 edition of the Statistical Atlas (privately published as Scribner’s Statistical Atlas of the United States) also used Gannett’s groupings of States. The chapter on physical geography has a section on “Natural Grouping of States,” including a map of the five major geographic divisions. The chapter on population has a few short tables that group the States by these geographic divisions.
Table 6-2. Shifts in the Naming and Arrangement of Regions and Divisions
| 1880–1890 | 1900 | 1910–1940 | 1950–1990 |
| North Atlantic | North Atlantic New England Southern North Atlantic | North New England Middle Atlantic East North Central West North Central | Northeast New England Middle Atlantic |
| Northern Central | North Central Eastern North Central Western North Central | | Midwest (name changed from North Central in 1984) East North Central West North Central |
| South Atlantic | South Atlantic Northern South Atlantic Southern South Atlantic | South South Atlantic East South Central West South Central | South South Atlantic East South Central West South Central |
| South Central | South Central Eastern South Central Western South Central | South South Atlantic East South Central West South Central | South South Atlantic East South Central West South Central |
| Western | Western Basin and Plateau Pacific Rocky Mountain | West Mountain Pacific | West Mountain Pacific |
The publications for the 1870 through the 1900 census reflected a continuing interest in the use of counties as geographic building blocks for regions, particularly those regions based on physiography, topography, drainage basins, or river systems. Over the period 1850 through 1900, the number of counties and statistically equivalent entities increased from 1,621 to 2,828; the 1900 layout of county areas and boundaries largely resembled the present pattern. For census purposes, counties were becoming a stable framework of geographic units; this development favored their use as building blocks for data tabulation and presentation. They also served the need for a smaller set of geographic units on which to base regional configurations.
The Census Office’s 1874 Statistical Atlas contained a discussion of the physical features of the country, prepared by Professor J. D. Whitney. The atlas had no accompanying statistical tables, but Whitney’s discussion of physiographic regions in the text became the basis for a presentation of data by regions based on physical features in the 1880 census report. Before the publication of the 1874 text in the statistical atlas, the 1850 and 1860 census mortality tables also made partial use of county groupings as summary areas.
Gannett continued this approach in the 1880, 1890, and 1900 census publications. The 1880 census report presents some summary data by 21 topographic regions, a practice continued in the publications of the 1890 census and, with minor modifications, the 1900 census as well. The population report for 1890 focused extensively on geographic distributions by natural regions. These included not only demographic statistics by topographic divisions, but also others: drainage basins, altitude, mean annual temperature, and rainfall. All 1890 census tables contained historical information from 1870 and 1880 recomputed or rearranged to conform to topographic regions and other areas shown in maps from the 1874 Statistical Atlas. The 1900 census publication continued these presentations.
A 1900 census report shows the 19 topographic divisions delineated for that census, and lists the number of counties and statistically equivalent entities in each division. Geographic arrangements of natural regions present a ​different picture from any groupings of States because most of the topographic divisions subdivide States and comprise portions of several States. Delaware, Iowa, Nevada, and the six New England States are the only States that appear in their entirety within their division. Figure 6-5 shows the 19 topographic divisions delineated for the 1900 population census report, and lists the number of counties and statistically equivalent entities in each division.
Figure 6-5. 1900 Census Topographic Divisions Based on Physiography
Number of Counties in Each Topographic Division
| New England Hills | 91 |
| Coast Lowlands | 99 |
| Coastal Plain (east of Mississippi River) | 278 |
| Piedmont Region | 189 |
| Appalachian Valley | 129 |
| Allegheny Plateau | 181 |
| Lake Region | 223 |
| Interior Timbered Region | 293 |
| Mississippi Alluvial Region | 60 |
| Prairie Region | 614 |
| Ozark Hills | 59 |
| Coastal Plain (west of Mississippi River) | 110 |
| Great Plains | 227 |
| Rocky Mountains | 73 |
| Columbian Mesas | 37 |
| Great Basin | 45 |
| Plateau Region | 32 |
| Pacific Valley | 57 |
| Coast Ranges | 31 |
Total Counties and Statistically Equivalent Entities in the Continental United States: 2,828
​A 1900 Census Office bulletin stated that in order for topographic divisions to serve statistical purposes, the lines between them must coincide with the boundaries of areas for which statistics are given separately by the census. Since the smallest available entity at that time was the county, Gannett adjusted the topographic division boundaries to coincide with county lines. To this day, one of the most basic operational rules of the Census Bureau’s geographic hierarchy is that geographic statistical entities for presenting census data must correspond to the geographic units for which the information otherwise is collected or tabulated. In delineating the divisions, he found that it was necessary to balance the different variables of geology, topography, altitude, rainfall, and temperature in order to create a physically homogeneous geographic entity enclosed by county boundaries.
Aside from Gannett’s participation in delineating geographic divisions, both for the decennial census publications from 1880 through 1900, and for historical compilations involving the 1870 statistics by county, his observations set forth in the 1900 Census Office bulletin also include the mention of geographic splits; that is, the operational subdivision of existing collection units that must serve as the building blocks for some different kind of geographic entity in a data tabulation or publication. This practice continues in selected census tabulations; for instance, the Census Bureau frequently splits other standard geographic units to provide data for entities such as incorporated places (see Chapter 9, “Places”).
By the late 19th Century, the geographic designations Northeast, South, Interior, and West had come to mean much the same as they do today. This general acceptance undoubtedly favored the retention of the 1880 pattern of State groupings in the Census Bureau’s statistical presentations rather than creating other combinations. Starting with the 1900 census, the statistical tables presented fewer alternative geographic groupings; instead, they made increasing use of a single, standard set of summary areas. The introductory texts in subsequent publications of the Census ​Bureau tended to be shorter, with fewer presentations or explanations of other approaches.
The 1880 census grouping of States into divisions and major sections therefore became the geographic summary units recognized for all subsequent censuses from 1890 through 1990. With some minor modifications, Census Bureau publications used them throughout the first several decades of this century to present information from the censuses of population, agriculture, and industry. The same set of areas also were used during the 1930s and 1940s for the new censuses of business, construction, housing, and services.
The nine divisions as presently constituted, except for Alaska and Hawaii, first appeared in the population report of the 1910 decennial census. In addition to divisions, the report contained information for the North, South, and West sections, as well as a separate summary by States east and west of the Mississippi River. The 1910 Census of Agriculture used a similar arrangement, as did the decennial census of 1920.
The 1930 population and agriculture census publications also used nine geographic divisions; however, the population census omitted summarizing data for the three sections, as well as the designation of areas as east and west of the Mississippi River. The agriculture census reports continued to use the three major sections, North, South, and West. The 1940 population and housing census reports revived these three areas; they also continued to present statistics for the nine divisions. The 1950 census publications presented summaries for the same nine geographic divisions in use since 1910. At a higher level, some slight modifications took place—the use of the name region instead of section, and the rearrangement of the four northern divisions that composed the North Section into the Northeast and North Central Regions, each consisting of two geographic divisions. The 1960 census saw the addition of Alaska and Hawaii to the Pacific Division; the 1970 and 1980 census publications brought no further changes. Except for the 1984 renaming of the North ​Central Region as Midwest, the Census Bureau continued the same system of geographic units for the 1990 census publications.
Several Census Bureau publications use the regions and divisions to summarize data tabulations from the decennial censuses. Among these, the most important reports constitute chapters of major subject-matter fields that summarize population and housing characteristics. These reports present summaries of both complete-count and sample data from the census of population and housing for the Nation as a whole, as well as data for the regions, divisions, States, urban and rural areas, the metropolitan and nonmetropolitan categories, and the other basic geographic units. In addition, various presentations from the other censuses and sample surveys use regions and divisions as part of their geographic summary units.
Although the system of regions and divisions has remained largely unchanged for many decades, the data user community periodically suggests new approaches to large-area summary geography. The Census Bureau, in turn, examines these proposals and considers them as possible improvements to the existing framework of State groupings.
One major review took place after the 1950 census, when an interagency committee within the Department of Commerce compared the existing Census Bureau regions and divisions to other schemes of regionalization and assessed the usefulness of an alternative system. Because the existing State groupings resulted largely from tradition, with few major changes from the 1880 set of summary units, it seemed worthwhile to test these combinations by using more modern statistical approaches and techniques. The following ground rules guided the study:
* Socioeconomic homogeneity is the principal criterion for grouping States into regions.
* Each combination should consist of two or more adjacent States. ​
* Objective statistical analysis is the primary basis for the classification.
* The number of eventual combinations should range from 6 to 12.
By using various statistical indexes, it was possible to identify almost three-quarters of the States (34 out of 48) as homogeneous cores of a region or division. The remaining 14 States proved to be somewhat marginal; the statistical evidence was less certain; they fell between two regions and, therefore, could belong to either. It is interesting that the proposed new arrangement contained the same number of groupings (four regions and nine divisions) as the existing system. It retained the same names for the four regions, but made a number of changes in grouping the States. The proposal assigned many States that were on the border of an existing region to a different region, and some to entirely new divisions. For instance, it shifted Delaware, the District of Columbia, and Maryland from the South Region to the Middle Atlantic Division of the Northeast Region; it combined Texas, Oklahoma, Arizona, and New Mexico to form a Southwest Division within an expanded West Region; it grouped Nevada with the Pacific States as part of a Far West Division; and it revamped the South into two divisions, each comprising an upper and lower tier of States. It renamed all but two divisions (New England and the Middle Atlantic). Only three of the resulting nine divisions maintained their original State components: (1) New England, (2) the Plains (formerly West North Central), and (3) the Great Lakes (formerly East North Central).
This suggested reclassification had its merits, for on a purely statistical basis it provided a more homogeneous set of areas than any others then in use by the Department of Commerce. However, the new system did not win enough overall acceptance among data users to warrant adoption as an official new set of general-purpose State groupings. The previous development of many series of statistics, arranged and issued over long periods of time on the basis of the existing State groupings, favored the retention of the summary units of the current regions and divisions (see Figure 6-1).
​In the 1970s, the Federal Government developed another set of summary areas for use in statistical presentations based on groupings of States. The Office of Management and Budget (OMB) directed the use of Standard Federal Administrative Regions (SFARs) by all Federal agencies that publish regional data. The SFARs consist of ten regions that cover not only the 50 States and the District of Columbia, but also Guam, Puerto Rico, and the Virgin Islands of the United States. The resulting geographic pattern is quite different from the layout of census regions and divisions; New England is the only instance where the two sets of areas coincide.
The SFAR framework resulted from an OMB survey of State officials that sought an arrangement of States different from the traditional regions and divisions. The OMB directive prescribed that Federal agencies publishing data supplied directly by States use the SFARs for such presentations. Other arrangements were permissible, either for special analytical purposes or for maintaining the continuity of a historical data series. On this basis, the Census Bureau continued to use its system of regions and divisions in the 1980 and 1990 decennial census publications.
The Census Bureau has used a variety of statistical groupings of counties to present data in recent decades. Its most significant nationwide set of county combination schemes consisted of the State economic areas (SEAs) and economic subregions (ESRs) first defined for the 1950 census. The SEA/ESR framework provided a sub-State counterpart of regions and divisions; both groupings, the one using States and the other using counties, covered the entire United States. They both served as sets of general-purpose summary units in the Census Bureau’s statistical presentations for several censuses.
The SEAs and ESRs were the product of a special study that the Census Bureau sponsored in cooperation with the Bureau of Agricultural Economics, U.S. Department of Agriculture, and several State and private agencies. The statistical criteria looked for homogeneity of socioeconomic characteristics, industry, land use, and agriculture. In terms of size, each SEA had to contain at least 100,000 people and use counties as the building blocks. Each SEA usually consisted of several counties that, with certain rare exceptions, had to be contiguous. Moreover, within a State, the geographic pattern of the SEAs was designed to facilitate further combination across State lines into ESRs. The SEAs also took into account the framework of metropolitan areas that appeared for the first time in the 1950 census publications. Where a metropolitan area extended across a State line, the segment within each State comprised a single SEA.
The SEAs and ESRs appeared in several publications of the 1950 decennial census. The Census Bureau continued to use the SEA/ESR system, with minor changes, in its publications of the 1960 and 1970 decennial censuses. The boundaries and the component units of SEAs remained largely unchanged following their initial establishment. In the 1950 census, the Census Bureau reported data for 501 SEAs; in the 1960 census, for 509; and, in the 1970 and 1980 censuses, 510. The Census Bureau discontinued the tabulation and publication of summary data by SEAs ​and ESRs for the 1980 and 1990 censuses as a result of apparent user disinterest in this information.
Finally, the Census Bureau uses one other approach that combines counties. This county grouping is of the Census Bureau’s public-use microdata samples (PUMS). The PUMS data product differs from the standard printed reports, computer tapes, microfiche, and the like, that present statistical summaries of all responses, either of complete-count information or of information collected from only a sample of households. By contrast, the PUMS files use a sample of raw data for areas of 100,000 or greater population; PUMS areas typically comprise large cities, groupings of counties, or remainders of counties. From these samples, the data users can select and manipulate specific responses to create customized decennial census tabulations in much the same way as if they had collected the information in their own census or sample survey. Strictly speaking, the PUMS microdata areas are not official geographic units, as the Census Bureau provides neither totals nor summary information for them. Instead, they are part of an ad hoc geographic framework established for data users who wish to analyze the diverse relationships among responses to standard questions.
As geographic combinations, the regions and divisions are familiar within the data user community. The Census Bureau intends to continue preparing data tabulations for these entities as standard parts of its tabulation and publication programs in future decennial censuses of population and housing, its quinquennial agricultural and economic censuses, its many current sample surveys, and its other compilations and compendia. As part of its continuing effort to improve the definition and delineation of geographic areas for each decennial census, the Census Bureau’s Statistical Areas Committee will review the components of the regions and divisions to ensure that they continue to represent the most useful combinations of States and State equivalents.
​Table 6-3. Numeric Identification System for the SFARs
| | States | FIPS Codes |
| SFAR 01 | Connecticut | 09 |
| SFAR 01 | Maine | 23 |
| SFAR 01 | Massachusetts | 25 |
| SFAR 01 | New Hampshire | 33 |
| SFAR 01 | Rhode Island | 44 |
| SFAR 01 | Vermont | 50 |
| SFAR 02 | New Jersey | 34 |
| SFAR 02 | New York | 36 |
| SFAR 02 | Puerto Rico | 72 |
| SFAR 02 | Virgin Islands | 78 |
| SFAR 03 | Delaware | 10 |
| SFAR 03 | District of Columbia | 11 |
| SFAR 03 | Maryland | 24 |
| SFAR 03 | Pennsylvania | 42 |
| SFAR 03 | Virginia | 51 |
| SFAR 03 | West Virginia | 54 |
| SFAR 04 | Alabama | 01 |
| SFAR 04 | Florida | 12 |
| SFAR 04 | Georgia | 13 |
| SFAR 04 | Kentucky | 21 |
| SFAR 04 | Mississippi | 28 |
| SFAR 04 | North Carolina | 37 |
| SFAR 04 | South Carolina | 45 |
| SFAR 04 | Tennessee | 47 |
| SFAR 05 | Illinois | 17 |
| SFAR 05 | Indiana | 18 |
| SFAR 05 | Michigan | 26 |
| SFAR 05 | Minnesota | 27 |
| SFAR 05 | Ohio | 39 |
| SFAR 05 | Wisconsin | 55 |
| SFAR 06 | Arkansas | 05 |
| SFAR 06 | Louisiana | 22 |
| SFAR 06 | New Mexico | 35 |
| SFAR 06 | Oklahoma | 40 |
| SFAR 06 | Texas | 48 |
| SFAR 07 | Iowa | 19 |
| SFAR 07 | Kansas | 20 |
| SFAR 07 | Missouri | 29 |
| SFAR 07 | Nebraska | 31 |
| SFAR 08 | Colorado | 08 |
| SFAR 08 | Montana | 30 |
| SFAR 08 | North Dakota | 38 |
| SFAR 08 | South Dakota | 46 |
| SFAR 08 | Utah | 49 |
| SFAR 08 | Wyoming | 56 |
| SFAR 09 | Arizona | 04 |
| SFAR 09 | California | 06 |
| SFAR 09 | Guam | 66 |
| SFAR 09 | Hawaii | 15 |
| SFAR 09 | Nevada | 32 |
| SFAR 10 | Alaska | 02 |
| SFAR 10 | Idaho | 16 |
| SFAR 10 | Oregon | 41 |
| SFAR 10 | Washington | 53 |
| Region 1: Northeast | Division 1: New England | Division 1: New England | Division 2: Middle Atlantic | Division 2: Middle Atlantic |
| Region 1: Northeast | Maine | 11 | New York | 21 |
| Region 1: Northeast | New Hampshire | 12 | New Jersey | 22 |
| Region 1: Northeast | Vermont | 13 | Pennsylvania | 23 |
| Region 1: Northeast | Massachusetts | 14 |
| Region 1: Northeast | Rhode Island | 15 |
| Region 1: Northeast | Connecticut | 16 |
| Region 2: Midwest | Division 3: East North Central | Division 3: East North Central | Division 4: West North Central | Division 4: West North Central |
| Region 2: Midwest | Ohio | 31 | Minnesota | 41 |
| Region 2: Midwest | Indiana | 32 | Iowa | 42 |
| Region 2: Midwest | Illinois | 33 | Missouri | 43 |
| Region 2: Midwest | Michigan | 34 | North Dakota | 44 |
| Region 2: Midwest | Wisconsin | 35 | South Dakota | 45 |
| Region 2: Midwest | | | Nebraska | 46 |
| Region 2: Midwest | | | Kansas | 47 |
| Region 3: South | Division 5: South Atlantic | Division 5: South Atlantic | Division 6: East South Central | Division 6: East South Central |
| Region 3: South | Delaware | 51 | Kentucky | 61 |
| Region 3: South | Maryland | 52 | Tennessee | 62 |
| Region 3: South | District of Colombia | 53 | Alabama | 63 |
| Region 3: South | Virginia | 54 | Mississippi | 64 |
| Region 3: South | West Virginia | 55 |
| Region 3: South | North Carolina | 56 | Division 7: West South Central | Division 7: West South Central |
| Region 3: South | South Carolina | 57 | Arkansas | 71 |
| Region 3: South | Georgia | 58 | Louisiana | 72 |
| Region 3: South | Florida | 59 | Oklahoma | 73 |
| Region 3: South | | | Texas | 74 |
| Region 4: West | Division 8: Mountain | Division 8: Mountain | Division 9: Pacific | Division 9: Pacific |
| Region 4: West | Montana | 81 | Washington | 91 |
| Region 4: West | Idaho | 82 | Oregon | 92 |
| Region 4: West | Wyoming | 83 | California | 93 |
| Region 4: West | Colorado | 84 | Alaska | 94 |
| Region 4: West | New Mexico | 85 | Hawaii | 95 |
| Region 4: West | Arizona | 86 |
| Region 4: West | Utah | 87 |
| Region 4: West | Nevada | 88 |