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States and counties are the major legally defined political and administrative
units of the United States. As such, they serve as the primary geographic 
units for which the Bureau of the Census reports data. The Census Bureau
provides statistics for these entities in every decennial census of population
and housing, in every census of agriculture and governments, and in all the
economic censuses. It tabulates data for States and counties in postcensal
estimates and sometimes in its various intercensal sample surveys and pro-
jections as well. In certain circumstances, it classifies entities as the 

statis-

tical equivalents

of States or of counties for data presentation purposes. 

Because States, counties, and statistically equivalent entities are an integral
part of many Census Bureau data presentations, they occupy a prominent
position in the hierarchy of the basic geographic entities (see Figure 2-1 in
Chapter 2). Therefore, a major responsibility of the Census Bureau is to
maintain accurate maps and records of the boundaries and names of these
entities, and to identify their populations and other data items correctly
throughout the various phases of the census process. This chapter describes
the framework of the States, counties, and statistically equivalent entities
used by the Census Bureau, and explains their function as geographic units
in the process of data collection, tabulation, and dissemination. 

The United States comprises the 50 States and the District of Columbia. For
data presentation purposes, the Census Bureau treats the District of Colum-
bia as the statistical equivalent of a State. Depending upon Federal law and
the scope of a particular census, sample survey, estimate, or projection, the
Census Bureau may apply the same treatment to the territories under U.S.
sovereignty or jurisdiction; for the 1990 decennial census, these included
American Samoa, Guam, the Northern Mariana Islands, Palau, Puerto Rico,
and the Virgin Islands of the United States. For several other entities under
U.S. jurisdiction, the Census Bureau publishes only decennial census popu-
lation counts and area measurements; for the 1990 census, these were the

States, Counties, Equivalent  Entities   4-1

States, Counties, and  
Statistically Equivalent Entities 

Chapter 4

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4-2   States, Counties, Equivalent Entities

Midway Islands; Wake Island; Johnston Atoll; Navassa, Baker, Howland
and Jarvis Islands; Kingman Reef; and Palmyra Atoll. In recent decennial
censuses, the Census Bureau also provided statistics as State equivalents
for the Canal Zone and the Trust Territory of the Pacific Islands (see Chap-
ter 7, “Puerto Rico and the Outlying Areas”). The designation 

Common-

wealth

 is part of the official name of four States (Kentucky, Massachusetts,

Pennsylvania, and Virginia), of Puerto Rico, and of the Northern Mariana
Islands. In the interest of uniformity, the Census Bureau does not use the
term for its data presentations.

For most States, counties are the primary administrative divisions. There
are exceptions, however; Louisiana has parishes, while Alaska has boroughs
for the organized portion of its territory. Because a large part of Alaska
is not in any organized borough, the State and the Census Bureau coop-
eratively have subdivided the unorganized portion of Alaska into 

census

areas

 for the purposes of presenting statistical data. Three States (Mary-

land, Missouri, and Nevada) each have one city that is governmentally inde-
pendent of county organization; Virginia currently has 41 such cities. For
both legal and statistical presentation purposes, these independent cities
constitute primary administrative divisions of their States. Part of Yellow-
stone National Park in Montana is not within any county, therefore the
Census Bureau treats it as the statistical equivalent of a county. The District
of Columbia has no primary administrative divisions; the Census Bureau
treats its entire area as the statistical equivalent of both a State and a county.

The various entities that the Census Bureau treats as the statistical equiva-
lents of counties in Puerto Rico and the Outlying Areas (see Chapter 7 for
details) are as follows:

• American Samoa—3 districts and 2 islands; the counties in American

Samoa are treated as minor civil divisions

• Guam—the entire island

• The Northern Mariana Islands—4 municipalities

• Palau—16 States

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States, Counties, Equivalent Entities   4-3

• Puerto Rico—78 municipios

• The Virgin Islands of the United States—3 islands

Historical Background

The formation of States and counties has been an important theme in
the political and social history of the United States as the Nation acquired
new areas, settled them, and organized territorial, State, and local govern-
ments. The present State boundaries evolved as the Nation expanded
westward; at the same time, counties developed and spread as units of
local government and administration within the States and territories.
There were more than 2,000 counties formed in the period from 1790
to 1900. The various censuses of the United States have recognized
these governmental units since the earliest enumerations.

Origin of States and Statehood

The system of individual States within a Federal union has its roots in the
American colonial experience. By the time of the American Revolution,
the identity and boundaries of the original 13 States had been evolving
during 150 years of British colonization and settlement. Under British rule,
the colonial legislatures gradually achieved various degrees of autonomy
and self-government. The present Federal Union began in 1789 under the
Constitution. The original 13 States joined the United States by their act
of ratification. Article IV, Section 3, of the Constitution provides for the
admission of additional States. Thereby, both the national and State gov-
ernments share the power to admit additional States. In the future, as in
the past, an area could achieve statehood only by an act of Congress that
follows the broad guidelines of this Constitutional provision.

States, Territories, and the First Decennial Census

In the colonial period, census-taking was a familiar element of the Amer-
ican scene; the colonial authorities undertook 27 enumerations of the
various colonies between 1624 and 1773. Article I, Section 2, of the Con-
stitution calls for a population census as the basis for apportioning the
seats in the Congress. The requirement for a census and, implicitly, the
recognition of States in the geographic structure of the Census Bureau’s

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4-4   States, Counties, Equivalent Entities

data tabulations, became part of the new Federal Government’s powers
and duties.

The 1790 census, the first national enumeration of the United States, included
the original 13 States as well as other areas that later would be formed into
States. At that time, Virginia included what is now the State of West Virginia.
The first national census reported separate counts for the 

districts

 of Ken-

tucky, Maine, Vermont, and the area that is now Tennessee. The actual
enumeration covered only the settled area, or about one-third of the new
Nation’s land area. It excluded much of northern Maine, upstate New York,
and western and central Pennsylvania. West of the Alleghenies, the 1790
enumeration covered only a few settlements in present-day Kentucky and
Tennessee. It included only the eastern third of present-day Georgia, and
none of Alabama and Mississippi. However, it did not encompass any of
the Northwest Territory, because that area was not under the effective
control of the U.S. Government or any of the States.

Westward Expansion, New States, and the Decennial Census

New States generally originated as part of the process of western expansion
and settlement, with the exceptions of Maine (created from Massachusetts)
and West Virginia (created from Virginia). Census coverage followed closely
behind the addition of new territory; as the frontier moved west, successive
decennial enumerations covered the newly settled areas.

Identifying the many boundary shifts and name changes of the territories
is beyond the scope of this chapter, as is providing detailed comparisons
between the areas enumerated for the first time and the areas of the pres-
ent-day States. Nevertheless, it is worthwhile to mention briefly some of
these developments as they relate to the first coverage of areas in a decen-
nial census of the United States. The maps in Figure 4-1 show the bounda-
ries of the States and territories recognized for the 1790, 1850, and 1870
decennial censuses; the last major rearrangements of territorial bounda-
ries and names occurred in the 1850s and 1860s. Table 4-1 shows the first
decennial census that included the geographic area of each State, together
with the date when each State was admitted to the Union. By the time of

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States, Counties, Equivalent Entities   4-5

the 1870 census, except for the boundary separating the Dakotas and the
merger of the two territories that formed Oklahoma, the States and terri-
torial boundaries of the conterminous United States were essentially fixed.
For convenience, the list refers to the States in terms of their present area
and boundaries; except for the original 13, usually that area still was a terri-
tory or part of a territory at the time of its first Federal census, sometimes
with a different name.

In almost all cases, each State or part of a State (other than the original 13)
appeared in at least one decennial enumeration before it achieved state-
hood. The exception is Texas, which was an independent republic before
its admission to the Union in 1845 and first appeared in the 1850 census.
The 1880 census marked the first enumeration of Alaska. The 1890 census
added the Indian Territory and the Oklahoma Territory (combined in
1907 to form the State of Oklahoma), and also reported data for Ameri-
can Indian reservations in other States and territories. The geographic
coverage of the 1900 census, which added Hawaii, encompassed the
entire area of the present United States.

The Development and Spread of Counties

The county originated as an administrative unit in England; early settlers
brought the concept with them to the colonies. Throughout the colonial
period, counties evolved as units of local government or administration.
However, their importance varied from region to region in response to
different economic, social, and political conditions. Long before the Rev-
olution, three distinct systems had developed:

• In much of New England, the compact pattern of settlement favored

the town as the local governing body; the county, a geographic group-
ing of towns, tended to be a legal entity that existed for judicial rather
than general governmental purposes.

• In the South, with its dispersed farms and plantations, the county

became the most important unit of local administration; towns (or
townships) generally did not develop as local, self-governing units
in the New England tradition.

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4-6   States, Counties, Equivalent Entities

Table 4-1.  

Chronology of First Decennial Census Coverage of Each State

 Year of

 Census

 First Decennial

Census Coverage

Year Admitted

    to Statehood

The Original 13 States

1787 to 1790

District of Columbia

*

Vermont

1791

1790

Kentucky

1792

Tennessee

1796

Maine

1820

West Virginia

1863

Ohio

1803

1800

Indiana

1816

Mississippi

1817

Alabama

1819

Louisiana

1812

1810

Illinois

1818

Missouri

1821

Arkansas

1836

Michigan

1837

1820

    —

1830

Florida

1845

1840

Iowa

1846

Wisconsin

1846

Texas

1845

California

1850

Minnesota

1858

1850

Oregon

1858

Washington

1889

Utah

1896

New Mexico

1912

Kansas

1861

Nevada

1864

Nebraska

1867

1860

Colorado

1876

North Dakota

1889

South Dakota

1889

Arizona

1912

Montana

1889

1870

Idaho

1890

Wyoming

1890

1880

Alaska

1959

1890

Oklahoma

1907

1900

Hawaii

1959

* The District of Columbia was organized in 1800.

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States, Counties, Equivalent Entities   4-7

Figure 4-1.

 

 States and Territories in 1790, 1850, and 1870

The United States in 1790

The United States in 1850

The United States in 1870

Later boundaries are shown with dashed lines.

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4-8   States, Counties, Equivalent Entities

• In the Middle Colonies of New Jersey, New York, and Pennsylvania,

counties were important units of government, but they also contained
townships (towns in New York), that had varying degrees of recogni-
tion and significance for some local governmental functions.

These three systems of local government continued beyond the colonial
period and became embodied in State constitutions and legislative acts. The
1790 census reported data for 292 counties. As the Nation expanded west-
ward, the county form of local government followed; thus, the nineteenth
century was the most active period of county formation (see Table 4-2).

Table 4-2. 

 Number of Counties and Parishes in Early Decennial Censuses

Decennial Census

Number of Counties and Parishes

1790

292

1850

1,621

1870

2,247

1900

2,713

1920

3,041

The totals do not include statistical equivalents of counties (such as the inde-
pendent cities of St. Louis and Baltimore and the cities of Virginia, some of
which were independent as early as 1850).

The Northwest Ordinance provided for the establishment of local govern-
ment in the newly settled territories, which later would become States. It
empowered the territorial governors to create geographic divisions, which
subsequently could serve as constituent units for representation in the terri-
torial assembly. Legislators in the territories and new States usually laid out
counties for the entire area of the jurisdiction. As a result, when new States
gained admission to the Union, they often already had counties, although the
less-settled portions of the State might have only a few very large counties,
which would subsequently be subdivided as settlement expanded.

The process of county formation continued actively into the first two dec-
ades of the twentieth century. The largest single increase occurred in 1907

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States, Counties, Equivalent Entities   4-9

when Oklahoma became a State and organized 54 new counties from the
Indian Territory. There were other sizable increases in county formation
between 1910 and 1920, when Montana and Idaho almost doubled their
number of existing counties by adding 23 and 21 new counties, respectively.

Since 1920, there have been relatively few new counties formed; in fact,
only 12 States have formed new counties since then. Although Florida
added 13 counties in the 1920s, few other States created more than 1 or 2
per decade; some States even lost counties as a result of mergers. Table 4-3
shows the number of counties and statistically equivalent entities at the time
of the 1920 census and at the times of the six decennial censuses from 1940
through 1990. Most of the change in the number of statistically equivalent
entities represents an increase in the number of independent cities in
Virginia (from 20 at the time of the 1920 census to 41 for the 1980 and 1990
censuses) and the recognition of a variety of new entities statistically equiva-
lent to counties in Alaska beginning with the 1960 census.

Table 4-3.

  Number of Counties and Statistically Equivalent Entities for

the 1920 and the 1940 Through 1990 Decennial Censuses

Census
  Year

Counties/Statistical

Equivalents

Counties/

  Parishes

Independent Cities

1

and Other

Statistically Equivalent Entities

2

1920

3,064

3,041

23

1940

3,100

3,070

30

1950

3,103

3,070

33

1960

3,134

3,072

62

1970

3,141

3,069

72

1980

3,137

3,068

69

1990

3,141

3,070

71

1

 

The independent cities include Baltimore city, St. Louis city, Carson City (as of 1970),

  and the cities of Virginia.

2

 

Other statistically equivalent entities include the District of Columbia, the Alaska statis-

  tical areas, and that portion of Yellowstone National Park in Montana as of 1940. The
  entities statistically equivalent to counties in Alaska were known as election districts in
  1960, census divisions in 1970, and boroughs/census areas in 1980 and 1990.

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4-10   States, Counties, Equivalent Entities

Table 4-4 lists the number of counties and equivalent entities in each State
and the District of Columbia on January 1, 1990. Between the 1980 and 1990
decennial censuses, Arizona and New Mexico each established an additional
county, and Alaska established two additional boroughs. One of the bor-
oughs established in Alaska (Northwest Arctic) in effect replaced a census
area (Kobuk), resulting in a net increase of two statistically equivalent enti-
ties. Nevada formed the new county of Bullfrog in 1987; however, its crea-
tion was nullified by the courts in 1988. The total number of counties and
statistically equivalent entities at the time of the 1990 census was 3,141.
In Alaska, two additional entities, Denali borough (established December
1990) and Yakutat borough (established 1992), have been formed since
the 1990 census.

Legal/Statistical Basis for Census Bureau Recognition

States and the statistically equivalent entities for which the Census Bureau
tabulates data are legal entities, with boundaries prescribed by laws, treaties,
and other governmental actions. Title 13, United States Code, in Chapter 5,
“Censuses,” Subchapter II, sections 141 (a) and (b), mandates the counting
and tabulating of the population of the individual States and entities. There-
fore, the Census Bureau uses the States, the District of Columbia, and the
territories of the United States as a primary level of geography; it retains
their identity throughout the data collection, tabulation, and dissemination
phases of every census.

Counties and Statistically Equivalent Entities of the United States

Much the same situation applies to the Nation’s counties and other statis-
tically equivalent entities. All but a few of these entities are defined legally;
that is, they are created by State law or some other administrative action.
State constitutions or other laws generally specify counties (parishes in
Louisiana, boroughs in Alaska, independent cities in four States) as the
divisions of each State, and assign responsibilities to them for providing
various aspects of local government. On this basis, it is logical for the
Census Bureau to use these entities as the major geographic units in its
data products. In addition, because counties and similar entities generally
encompass the entire land area of each State and statistically equivalent

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States, Counties, Equivalent Entities   4-11

Table 4-4.

  Number of Counties and Statistically Equivalent Entities, by

State, as of January 1, 1990

Alabama

  67

Montana

  57

Alaska

  25

Nebraska

  93

Arizona

  15

Nevada

  17

Arkansas

  75

New Hampshire

  10

California

  58

New  Jersey

  21

Colorado

  63

New Mexico

  33

Connecticut

    8

New York

  62

Delaware

    3

North Carolina

100

District of Columbia

    1

North Dakota

  53

Florida

  67

Ohio

  88

Georgia

159

Oklahoma

  77

Hawaii

    5

Oregon

  36

Idaho

  44

Pennsylvania

  67

Illinois

102

Rhode Island

    5

Indiana

  92

South Carolina

  46

Iowa

  99

South Dakota

  66

Kansas

105

Tennessee

  95

Kentucky

120

Texas

254

Louisiana

  64

Utah

  29

Maine

  16

Vermont

  14

Maryland

  24

Virginia

136

Massachusetts

  14

Washington

  39

Michigan

  83

West Virginia

  55

Minnesota

  87

Wisconsin

  72

Mississippi

  82

Wyoming

  23

Missouri

115

United States Total:  3,141

The United States total includes 3,006 counties; 14 boroughs and 11 census areas in
Alaska; the District of Columbia; 64 parishes in Louisiana; Baltimore city, Maryland;
St. Louis city, Missouri; that part of Yellowstone National Park in Montana; Carson
City, Nevada; and 41 independent cities in Virginia.

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4-12   States, Counties, Equivalent Entities

entity, they constitute a detailed, relatively stable network of geographic
units at a single geographic/governmental level for the entire United States
and its territories. As such, they provide convenient units for data dissem-
ination purposes. Of course, because most of these entities represent
local governmental units, their officials, as well as the officials of State and
Federal agencies and other data users, require statistics for the counties
from each specific census. Because most censuses and sample surveys
use a single common set of counties and statistically equivalent entities,
the identification of individual county units constitutes an important ele-
ment in the Census Bureau’s work and in its data products.

Rhode Island’s counties exist only for the purpose of judicial administra-
tion and have no associated governmental structure. In 1960, Connecticut
abolished its county governments and transferred their functions to the
State government; however, the State retained the former counties for
election and judicial purposes. Nevertheless, in both States, the Census
Bureau continues to report many types of data for these county-type
entities, in part to retain data comparability with earlier censuses and
the data sets of other government agencies.

The Statistical Equivalents of Counties in Puerto Rico and the
Outlying Areas

For Puerto Rico and the Outlying Areas, the Census Bureau uses various
geographic units as the statistical equivalent of stateside counties. This
occurs where the size, geography, or administrative framework make
the units appropriate entities for such use. As in the 50 States, the statis-
tical equivalents of counties in the Outlying Areas provide complete geo-
graphic coverage for the entire area and population of each jurisdiction
(see Chapter 7).

Boundaries and Codes

To effectively collect, process, and tabulate data for States, counties,
and their statistically equivalent entities, the Census Bureau must ensure
that it has accurate records of the boundaries of, and names for, these
entities. The Census Bureau also must develop appropriate geographic

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States, Counties, Equivalent Entities   4-13

code schemes and geographic relationship files to properly control and
present the data it collects for these important governmental units.

Stability of State and County Boundaries

The boundaries of the primary governmental divisions of the United
States, States, counties, and their statistical equivalents, generally are static
and change only rarely; however, transfers of territory do occur from
time to time. By contrast, the boundaries of incorporated places and
even minor civil divisions are far more subject to change in most States.

Changes in State lines may result from legislation, court decisions, and
other types of governmental action; changes in county boundaries are
a matter of State law. Such boundary changes also may stem from more
exact geographic descriptions, better maps, and improved surveying
techniques. State boundaries may change by mutual agreement of the
two State legislatures, subject to approval by the Congress.

In recent years, most boundary changes for counties have been minor
and have not involved substantial shifts of population or land area. The
independent cities in Virginia constitute an exception because they
occasionally annex territory, as do the incorporated places in many
States. Because the territory annexed by a Virginia city no longer is part
of the county in which it had been located, changes in the boundaries
of these independent cities also affect the boundaries of the adjacent
county or counties. In other States, changes to counties occur on a
piecemeal basis.

The Boundary and Annexation Survey (BAS)

The Census Bureau has established procedures and programs to identify
changes in legal boundaries and to record when and where they occur.
The Census Bureau’s Boundary and Annexation Survey (BAS), conducted
at periodic intervals immediately before each decennial census, and annu-
ally since 1972, determines the location of the boundaries of most major
legal entities in the United States. The principal function of the BAS is to
collect and maintain information on the inventory, status, boundaries,

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4-14   States, Counties, Equivalent Entities

and names of local governments (counties, minor civil divisions, and
incorporated places), and to ascertain whether changes have occurred in
these entities. The Census Bureau obtains information about counties by
sending questionnaires and maps to an official of each county (parish in
Louisiana) in the United States, excluding Alaska, Connecticut, Hawaii, and
Rhode Island; in these States, because of the unusual status of the counties
(boroughs in Alaska), the Census Bureau works with the appropriate State
authorities to obtain the required information. However, new counties
(and boroughs in Alaska) are such a rare and major event that they usually
come to the Census Bureau’s attention long before, and separate from, the
annual BAS mailout. The Census Bureau obtains official confirmation and
documentation of new counties, their boundaries, and their names from
appropriate State officials.

Any changes in county boundaries may reflect changes in State bounda-
ries as well. The proper location of State and county boundaries on Cen-
sus Bureau maps is a vital element of the data collection and tabulation
process. The BAS enables the Census Bureau to maintain, on a consistent
basis, reasonably current records about changes in county boundaries
that occur through resurveying, legal actions, or other transfers of terri-
tory that relocate county lines. In this way, the Census Bureau also accounts
for changes in State lines as reported by the counties on either side of the
State boundary.

State and County Codes

The Census Bureau uses a system of numeric codes to identify every geo-
graphic entity in its hierarchy. These geographic codes are basic compo-
nents of the geographic reference files that the Census Bureau develops
and maintains to process the results of its censuses and sample surveys.
The codes obviate the need to relate data to the geographic entities by
name; that is, the Census Bureau’s processing operations associate data
with the much shorter, fixed-length, unique numeric codes rather than
the variable-length names of the geographic entities in its reference files.
These files provide the basis for the tabulation and dissemination of the
collected data in their proper geographic units.

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States, Counties, Equivalent Entities   4-15

The Federal Government uses a unique two-digit numeric code to identify
each State and State equivalent entity. These State codes are part of the
Federal Information Processing Standards (FIPS), an official coding sys-
tem developed by the National Institute of Standards and Technology
(NIST, formerly the National Bureau of Standards), U.S. Department of
Commerce, and maintained by the U.S. Geological Survey (USGS). These
FIPS codes parallel the alphabetic sequence of State names, including
the District of Columbia, followed by Puerto Rico and the Outlying Areas
in alphabetical order (see Table 4-5). Gaps left in the State numbering
sequence provide for the possibility that a major Outlying Area may attain
statehood using its current name. In addition, the FIPS for States includes
a two-letter alphabetic code, used by both the NIST and the U.S. Postal
Service, which has been adopted by many other Federal agencies.

In addition to the FIPS codes for States, the Census Bureau devised and
uses a system of two-digit codes to identify each State in a geographic
sequence within its census division. Each of the nine census divisions
encompasses a group of adjacent States; the first digit of the Census
Bureau’s State code identifies the division and the second digit refers to
the geographic sequence of the individual State within that division. The
territories under U.S. jurisdiction are not assigned to any of the nine cen-
sus divisions, and their codes have a first digit of 0 in the Census Bureau’s
scheme (see Table 4-5). Chapter 6, “Statistical Groupings of States and
Counties,” presents a discussion of the census regions and divisions.

Another FIPS coding scheme that the Census Bureau uses identifies the
counties alphabetically within each State. The FIPS 6 publication assigns
each county a three-digit numeric code, with gaps in the numbering
sequence to allow for additions and revisions. The independent cities
appear at the end of the county list for each appropriate State, begin-
ning with code 510.

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4-16   States, Counties, Equivalent Entities

Table 4-5.

  Federal Abbreviations and Numeric Identification Codes for States,

Outlying Areas, and Other Entities

State/Statistically

FIPS/USPS

FIPS

Census

Equivalent Entity

Abbreviation

Code

Code

Alabama

AL

01

63

Alaska

AK

02

94

Arizona

AZ

04

86

Arkansas

AR

05

71

California

CA

06

93

Colorado

CO

08

84

Connecticut

CT

09

16

Delaware

DE

10

51

District of Columbia

DC

11

53

Florida

FL

12

59

Georgia

G A

13

58

Hawaii

H I

15

95

Idaho

I D

16

82

Illinois

IL

17

33

Indiana

IN

18

32

Iowa

IA

19

42

Kansas

KS

20

47

Kentucky

KY

21

61

Louisiana

LA

22

72

Maine

ME

23

11

Maryland

MD

24

52

Massachusetts

MA

25

14

Michigan

MI

26

34

Minnesota

MN

27

41

Mississippi

MS

28

64

Missouri

M O

29

43

Montana

MT

30

81

Nebraska

NE

31

46

Nevada

NV

32

88

New Hampshire

N H

33

12

New Jersey

NJ

34

22

New Mexico

NM

35

85

New York

NY

36

21

North Carolina

NC

37

56

North Dakota

ND

38

44

Ohio

O H

39

31

Oklahoma

O K

40

73

Oregon

OR

41

92

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States, Counties, Equivalent Entities   4-17

Table 4-5.

  

(cont.)

State/Statistically

FIPS/USPS

FIPS

Census

Equivalent Entity

Abbreviation

Code

Code

Pennsylvania

PA

42

23

Rhode Island

RI

44

15

South Carolina

SC

45

57

South Dakota

S D

46

45

Tennessee

TN

47

62

Texas

TX

48

74

Utah

UT

49

87

Vermont

VT

50

13

Virginia

VA

51

54

Washington

W A

53

91

West Virginia

WV

54

55

Wisconsin

W I

55

35

Wyoming

WY

56

83

American Samoa

AS

60

03

Guam

GU

66

04

Northern Mariana Islands

MP

69

01

Palau

PW

70

02

Puerto Rico

PR

72

06

U.S. Virgin Islands

 

VI

78

07

Foreign Areas and International Waters

1

_     

99   

_

U.S. Minor Outlying Islands

2

O M

74

08

Baker Island

81

08

Howland Island

84

08

Jarvis Island

86

08

Johnston Atoll

67

08

Kingman Reef

89

08

Midway Islands

71

08

Navassa Island

76

08

Palmyra Atoll

95

08

Wake Island

79

08

1

 

Foreign Areas and International Waters are areas bordering the United States and the Outlying

Areas. They have no official NIST/USPS abbreviation and require no State-level code.

2

 

The individual islands of the U.S. Minor Outlying Islands have no official NIST/USPS abbreviation.

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4-18   States, Counties, Equivalent Entities

Relationships to Other Geographic Entities

Both States and counties provide complete coverage of all land area and
population in the United States at their geographic levels. Almost all other
geographic entities included in the Census Bureau’s data tabulations respect
the boundaries of States. American Indian reservations, however, may cross
State boundaries. Also, some U.S. Postal Service five-digit ZIP Codes extend
into a second State. By design, statistical areas respect State lines, with two
exceptions: both metropolitan areas (defined by the Office of Management
and Budget) and urbanized areas may cross State boundaries.

Combinations of States and Counties

Two types of statistical entities, the census region and the census division,
encompass combinations of adjacent States. Both regions and divisions are
convenient geographic units for summarizing census and sample survey
data. For instance, the six New England States compose a single division;
together with the Middle Atlantic Division, they form the Northeast Region
(see Chapter 6, “Statistical Groupings of States and Counties”).

The nationwide geographic framework provided by the county makes it
possible to combine counties and statistically equivalent entities into larger
statistical units, which may encompass an entire State or selected parts of
several States. One of the best known examples of county combinations
are metropolitan areas (see Chapter 13, “Metropolitan Areas”).

Relationships in the Census Bureau’s Geographic Hierarchy

At lower levels of the geographic hierarchy, most geographic areas respect
the boundaries of counties and county equivalents. The county subdivisions,
census county divisions, minor civil divisions, and unorganized territories,
provide complete coverage of all land area and population within each
county and statistically equivalent entity. On the other hand, in most States,
incorporated places may cross county lines; census designated places may
do so in all States. Some incorporated places, such as Philadelphia and
San Francisco, comprise the entire area of a county (the city of New York
encompasses five entire counties); for such entities, the city and county
usually have a single government. In five instances at the time of the 1990

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States, Counties, Equivalent Entities   4-19

census, a county and city consolidated their governments, and yet other
incorporated places continued to function within the county; the Census
Bureau treats these entities as both counties and consolidated cities (see
Chapter 9, “Places”). The small-area components of decennial census
geography, census tracts/block numbering areas and their subdivisions
(block groups and census blocks, and enumeration districts prior to the
1990 census), always observe county boundaries.


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