Census tract
Encyclopedia
A census tract, census area, or census district is a geographic region defined for the purpose of taking a census
. Usually these coincide with the limits
of cities, town
s or other administrative areas and several tracts commonly exist within a county. In unincorporated area
s of the United States these are often arbitrary, except for coinciding with political lines
.
Census tracts represent the smallest territorial unit for which population data are available in many countries. In the United States, census tracts are subdivided into block groups
and census block
s. In Canada they are divided into dissemination areas. In the U.S., Census tracts are "Designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions, census tracts average about 4,000 inhabitants."U.S. Census Bureau definition
. For the 1910 Census
, eight cities—New York, Baltimore
, Boston
, Chicago
, Cleveland, Philadelphia, Pittsburgh, and St. Louis—delineated census tracts (then termed ‘‘districts’’) for the first time. No additional jurisdictions delineated census tracts until just prior to the 1930 Census
, when an additional ten cities chose to do so. The increased interest in census tracts for the 1930 Census is attributed to the promotional efforts of Howard Whipple Green, who was a statistician in Cleveland
, Ohio
, and later the chairman of the American Statistical Association’s Committee on Census Enumeration Areas. For more than twenty-five years, Mr. Green strongly encouraged local citizens, via committees, to establish census tracts and other census statistical geographic areas. The committees created by local citizens were known as Census Tract Committees, later called Census Statistical Areas Committees.
After 1930, the Census Bureau saw the need to standardize the delineation, review, and updating of census tracts and published the first set of census tract criteria in 1934. The goal of the
criteria has remained unchanged; that is, to assure comparability and data reliability through the standardization of the population thresholds for census tracts, as well as requiring that their
boundaries follow specific types of geographic features that do not change frequently. The Census Bureau began publishing census tract data as part of its standard tabulations beginning with
the 1940 Census
. Prior to that time, census tract data were published as special tabulations.
For the 1940 Census, the Census Bureau began publishing census block data for all cities with 50,000 or more people. Census block
numbers were assigned, where possible, by census
tract, but for those cities that had not yet delineated census tracts, ‘‘block areas’’ (called ‘‘block numbering areas’’ [BNAs] in later censuses) were created to assign census block numbers.
Starting with the 1960 Census
, the Census Bureau
assumed a greater role in promoting and coordinating the delineation, review, and update of census tracts. For the 1980 Census
, criteria for BNAs were changed to make them more comparable in size and shape to census tracts. For the 1990 Census
, all counties contained either census tracts or BNAs.
Census 2000
was the first decade in which census tracts were defined in all counties. In addition, the Census Bureau increased the number of geographic areas whose boundaries could be used as census tract boundaries. It also allowed tribal governments of federally recognized American Indian tribes with a reservation and/or off-reservation trust lands to delineate tracts without regard to State and/or county boundaries, provided the tribe had a 1990 Census population of at least 1,000.
. The Inter-University Census Tract Committee was formed in 1955 and Oxford was divided into 48 tracts with an average population of 2,645 each. The Registrar General
, however, opted for enumeration districts containing less than 1,000 people on average, rather than adopting census tracts. While tracts composed of enumeration districts were later developed, these were not extensively used. Census tracts have, however, been constructed and used by British demographers. The Office for National Statistics
now uses enumeration districts only for the collection of data, with output areas used as the base unit in census releases.
Census
A census is the procedure of systematically acquiring and recording information about the members of a given population. It is a regularly occurring and official count of a particular population. The term is used mostly in connection with national population and housing censuses; other common...
. Usually these coincide with the limits
Border
Borders define geographic boundaries of political entities or legal jurisdictions, such as governments, sovereign states, federated states and other subnational entities. Some borders—such as a state's internal administrative borders, or inter-state borders within the Schengen Area—are open and...
of cities, town
Town
A town is a human settlement larger than a village but smaller than a city. The size a settlement must be in order to be called a "town" varies considerably in different parts of the world, so that, for example, many American "small towns" seem to British people to be no more than villages, while...
s or other administrative areas and several tracts commonly exist within a county. In unincorporated area
Unincorporated area
In law, an unincorporated area is a region of land that is not a part of any municipality.To "incorporate" in this context means to form a municipal corporation, a city, town, or village with its own government. An unincorporated community is usually not subject to or taxed by a municipal government...
s of the United States these are often arbitrary, except for coinciding with political lines
Political geography
Political geography is the field of human geography that is concerned with the study of both the spatially uneven outcomes of political processes and the ways in which political processes are themselves affected by spatial structures...
.
Census tracts represent the smallest territorial unit for which population data are available in many countries. In the United States, census tracts are subdivided into block groups
Census block group
A census block group is a geographical unit used by the United States Census Bureau which is between the census tract and the census block. It is the smallest geographical unit for which the bureau publishes sample data, i.e data which is only collected from a fraction of all households.Census...
and census block
Census block
A census block is the smallest geographic unit used by the United States Census Bureau for tabulation of 100-percent data . Several blocks make up block groups, which again make up census tracts. There are on average about 39 blocks per block group, but there are variations...
s. In Canada they are divided into dissemination areas. In the U.S., Census tracts are "Designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions, census tracts average about 4,000 inhabitants."U.S. Census Bureau definition
United States
The concept of the census tract was first developed in the United States. In 1906, Dr. Walter Laidlaw originated the concept of permanent, small geographic areas as a framework for studying change from one decennial census to another in neighborhoods within New York CityNew York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
. For the 1910 Census
United States Census, 1910
The Thirteenth United States Census, conducted by the Census Bureau on April 15, 1910, determined the resident population of the United States to be 92,228,496, an increase of 21.0 percent over the 76,212,168 persons enumerated during the 1900 Census...
, eight cities—New York, Baltimore
Baltimore
Baltimore is the largest independent city in the United States and the largest city and cultural center of the US state of Maryland. The city is located in central Maryland along the tidal portion of the Patapsco River, an arm of the Chesapeake Bay. Baltimore is sometimes referred to as Baltimore...
, Boston
Boston
Boston is the capital of and largest city in Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is regarded as the unofficial "Capital of New England" for its economic and cultural impact on the entire New England region. The city proper had...
, Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
, Cleveland, Philadelphia, Pittsburgh, and St. Louis—delineated census tracts (then termed ‘‘districts’’) for the first time. No additional jurisdictions delineated census tracts until just prior to the 1930 Census
United States Census, 1930
The Fifteenth United States Census, conducted by the Census Bureau one month from April 1, 1930, determined the resident population of the United States to be 122,775,046, an increase of 13.7 percent over the 106,021,537 persons enumerated during the 1920 Census.-Census questions:The 1930 Census...
, when an additional ten cities chose to do so. The increased interest in census tracts for the 1930 Census is attributed to the promotional efforts of Howard Whipple Green, who was a statistician in Cleveland
Cleveland, Ohio
Cleveland is a city in the U.S. state of Ohio and is the county seat of Cuyahoga County, the most populous county in the state. The city is located in northeastern Ohio on the southern shore of Lake Erie, approximately west of the Pennsylvania border...
, Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
, and later the chairman of the American Statistical Association’s Committee on Census Enumeration Areas. For more than twenty-five years, Mr. Green strongly encouraged local citizens, via committees, to establish census tracts and other census statistical geographic areas. The committees created by local citizens were known as Census Tract Committees, later called Census Statistical Areas Committees.
After 1930, the Census Bureau saw the need to standardize the delineation, review, and updating of census tracts and published the first set of census tract criteria in 1934. The goal of the
criteria has remained unchanged; that is, to assure comparability and data reliability through the standardization of the population thresholds for census tracts, as well as requiring that their
boundaries follow specific types of geographic features that do not change frequently. The Census Bureau began publishing census tract data as part of its standard tabulations beginning with
the 1940 Census
United States Census, 1940
The Sixteenth United States Census, conducted by the Census Bureau, determined the resident population of the United States to be 132,164,569, an increase of 7.3 percent over the 1930 population of 123,202,624 persons. The census date was April 1, 1940...
. Prior to that time, census tract data were published as special tabulations.
For the 1940 Census, the Census Bureau began publishing census block data for all cities with 50,000 or more people. Census block
Census block
A census block is the smallest geographic unit used by the United States Census Bureau for tabulation of 100-percent data . Several blocks make up block groups, which again make up census tracts. There are on average about 39 blocks per block group, but there are variations...
numbers were assigned, where possible, by census
tract, but for those cities that had not yet delineated census tracts, ‘‘block areas’’ (called ‘‘block numbering areas’’ [BNAs] in later censuses) were created to assign census block numbers.
Starting with the 1960 Census
United States Census, 1960
The Eighteenth United States Census, conducted by the Census Bureau, determined the resident population of the United States to be 179,323,175, an increase of 18.5 percent over the 151,325,798 persons enumerated during the 1950 Census.-Census questions:...
, the Census Bureau
United States Census Bureau
The United States Census Bureau is the government agency that is responsible for the United States Census. It also gathers other national demographic and economic data...
assumed a greater role in promoting and coordinating the delineation, review, and update of census tracts. For the 1980 Census
United States Census, 1980
The Twentieth United States Census, conducted by the Census Bureau, determined the resident population of the United States to be 226,545,805, an increase of 11.4 percent over the 203,184,772 persons enumerated during the 1970 Census.-Census questions:...
, criteria for BNAs were changed to make them more comparable in size and shape to census tracts. For the 1990 Census
United States Census, 1990
The Twenty-first United States Census, conducted by the Census Bureau, determined the resident population of the United States to be 248,709,873, an increase of 9.8 percent over the 226,545,805 persons enumerated during the 1980 Census....
, all counties contained either census tracts or BNAs.
Census 2000
United States Census, 2000
The Twenty-second United States Census, known as Census 2000 and conducted by the Census Bureau, determined the resident population of the United States on April 1, 2000, to be 281,421,906, an increase of 13.2% over the 248,709,873 persons enumerated during the 1990 Census...
was the first decade in which census tracts were defined in all counties. In addition, the Census Bureau increased the number of geographic areas whose boundaries could be used as census tract boundaries. It also allowed tribal governments of federally recognized American Indian tribes with a reservation and/or off-reservation trust lands to delineate tracts without regard to State and/or county boundaries, provided the tribe had a 1990 Census population of at least 1,000.
United Kingdom
British census tracts were first developed in the city of OxfordOxford
The city of Oxford is the county town of Oxfordshire, England. The city, made prominent by its medieval university, has a population of just under 165,000, with 153,900 living within the district boundary. It lies about 50 miles north-west of London. The rivers Cherwell and Thames run through...
. The Inter-University Census Tract Committee was formed in 1955 and Oxford was divided into 48 tracts with an average population of 2,645 each. The Registrar General
Registrar General
General Register Office, in England and Wales, Scotland, Ireland, and many Commonwealth nations, is the government agency responsible for civil registration - the recording of vital records such as births, deaths, and marriages...
, however, opted for enumeration districts containing less than 1,000 people on average, rather than adopting census tracts. While tracts composed of enumeration districts were later developed, these were not extensively used. Census tracts have, however, been constructed and used by British demographers. The Office for National Statistics
Office for National Statistics
The Office for National Statistics is the executive office of the UK Statistics Authority, a non-ministerial department which reports directly to the Parliament of the United Kingdom.- Overview :...
now uses enumeration districts only for the collection of data, with output areas used as the base unit in census releases.
External links
- Chapter 10: Census Tracts and Block Numbering Areas, U.S. Census Bureau, Geographic Areas Reference Manual (PDF)
- gCensus: Browse Tract Numbers, Block Group Numbers, and Block Numbers