# Presentation: 817634

## Census 2000:

**Geographic Concepts**** **

**Notes:**
This presentation is designed to give novice users a quick overview of the many geographic concepts and units that the Census Bureau uses in conducting the decennial census.

## Small-Area Geography Overview

**Notes:**
In census geography, we start with the most basic unit, the census block.  As you can see in this illustration, for some of the more common census geographic units they nest within the larger unit all the way up to the county level.  Now we’ll take a closer look at these individual units.

## Blocks

- Smallest units of data tabulation
- Cover the entire nation
- Do not cross census tracts or counties
- Generally bounded by visible features and legal boundaries
- Block numbers completely different from 1990
- Size: average about 100 people

**Notes:**
A block is defined as an area bounded on all sides by visible and/or invisible features shown on a map prepared by the U.S. Census Bureau. A block is the smallest geographic entity for which the Census Bureau tabulates decennial census data.
There are about 8,200,000 blocks delineated for Census 2000.
There has been a complete renumbering of blocks across the U.S.  One other major change is that the numbering has gone from a three-digit system to a four-digit system.  Water bodies were also assigned block numbers in Census 2000 for the first time.  

Speaker Note:  The Census Bureau used different “collection block numbers” for the precensus period and collection of data.  For delineation purposes different “tabulation block numbers” have been assigned. Block numbers for the precensus and census activities ignored many legal boundaries, whereas for data tabulation, the Census Bureau held every tabulation area boundary as a block boundary.  Basically, tabulation area boundaries are those block boundaries taken as a snapshot of geography on January 1, 2000.   

## Census Block Map

**Notes:**
Here you’ll see an excerpt from a Census 2000 Block Map for Broward County, Florida. You can see on the map the large red numbers indicating the census tract.  Census tracts which we will define in a later slide, are always four primary digits.  In this example you’ll note that the census tract number 204.11 is missing the its leading zero and displays only 3 primary digits.  The two-digit suffix .11 indicates that the census tract 0204 has been divided due to population growth. Nested within the census tract are smaller 4-digit red numbers indicating the individual blocks.  You’ll note that the map shows the road names that correspond to many of the block boundaries. 

Speaker Note: The Census Bureau will prepare the following files for relationship comparisons of 1990 blocks to Census 2000 blocks:
- 1990 tabulation census block to Census 2000 collection block 
- Census 2000 collection block to Census 2000 tabulation block 
- 1990 Census tabulation block to Census 2000 tabulation block 
These will be available beginning in May 2001, on CD-ROM and Internet: (www.census.gov/geo/www/calculate/relate/rel_blk.html).  

The Census Bureau will create census block relationship information on the basis of one-to-one, one-to-many and many-to-one block(s). The purpose of the relationship files is to show how 1990 census blocks now relate to Census 2000 blocks. They do not depict the actual spatial relationships between census blocks.

## Block Groups

- Groups of blocks sharing the same first digit
- Smallest areas for which sample data available
- Size: optimally 1,500 people, range between 300 to 3,000

**Notes:**
A statistical subdivision of a census tract (or, prior to Census 2000, a block numbering area), a block group consists of a cluster of census blocks having the same first digit of their identifying numbers within that tract. 
For example, for Census 2000, BG 3 within a census tract includes all blocks numbered from 3000 to 3999. (A few BGs consist of a single block.) BGs generally contain between 300 and 3,000 people, with an optimum size of 1,500 people. 
The BG is the lowest-level geographic entity for which the U.S. Census Bureau tabulates sample data from a decennial census.

## Census Tracts

- For the first time for Census 2000: Cover the nation
- Relatively homogenous population characteristics
- 65,000 Census tracts across U.S.
- Size: optimally 4,000 people, range between 1,000 and 8,000

**Notes:**
Census tracts are small, relatively permanent statistical subdivisions of a county or a statistically equivalent entity. Designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions at the time they are established, census tracts generally contain between 1,000 and 8,000 people, with an optimum size of 4,000 people. Census tract boundaries are delineated with the intention of being stable over many decades, so they generally follow relatively permanent visible features. However, they may follow governmental unit boundaries and other invisible features in some instances; the boundary of a state or county is always a census tract boundary.
Census tracts are usually identified by a six-digit number composed of a four-digit basic number and a two-digit numeric suffix; for example, 8001.07.  This suffix (.07) indicates that the original tract, tract 8001, was split possibly into seven pieces as a result of population growth.  In some maps the census tract may be represented by a single digit number - in those cases the three leading zeroes were omitted for simplification.  However, all census tracts have 6 digits (first four and the last two after the decimal).  
In 1990 and previous censuses, the Census Bureau  created tract-like geographic units, called Block Numbering Areas or BNAs, outside of metropolitan areas.  BNAs were discontinued for Census 2000; instead, one or more census tracts were identified for every county and statistically equivalent entity. 

Speaker Notes: Census tracts are usually delineated for data presentation purposes by a local group of census data users or the geographic staff of a regional census center in accordance with U.S. Census Bureau guidelines. 

## Block Groups and Census Tracts

**Notes:**
Here we see an example of a Reference Map prepared with the Census Bureau’s online data retrieval and mapping tool: American FactFinder.  You’ll note here how the census tract labeled 8001.07 is bounded by the auburn boundary.  In this map, as opposed to the earlier County Block Map example, the census tract numbers do display all 4 primary digits.  Inside the tract, there are the four-digit block numbers in yellow and you can also see the block groups outlined in the peach boundaries and labeled with single-digits.  

## Places

- Incorporated Places
- Census Designated Places

**Notes:**
There are two kinds of places in Census Bureau terminology: incorporated places and Census Designated Places (CDPs).  
A place is a concentration of population legally bounded as an incorporated place. A CDP is delineated for statistical purposes as a census designated place (in Puerto Rico, a comunidad or zona urbana).  These are created for the purpose of presenting census data for an area with a concentration of population, housing, and commercial structures that is identifiable by name, but is not within an incorporated place. For Census 2000, for the first time, CDPs did not need to meet a minimum population threshold to qualify for tabulation of census data.  
As you can see in this map taken from the American FactFinder, the boundaries of places - either incorporated or CDPs - do NOT necessarily correspond to census tracts, block groups or MCDs.  

Speaker note: CDP boundaries, which usually coincide with visible features or the boundary of an adjacent incorporated place or other legal entity boundary, have no legal status, nor do these places have officials elected to serve traditional municipal functions. CDPs usually are delineated in cooperation with state, Puerto Rico, Island Area, local, and tribal officials based on U.S. Census Bureau guidelines. 

## Minor Civil Divisions (MCD) orCensus County Divisions (CCD)

- Used to establish and maintain a set of subcounty units that have stable boundaries and recognizable names
- Do NOT have to follow minimum or maximum population guidelines

**Notes:**
A minor civil division (MCD) is the the primary governmental or administrative division of a county or statistically equivalent entity in many states and statistically equivalent entities. A minor civil division is created to govern or administer an area rather than a specific population.(ex. Town, Township, District)  The U.S. Census Bureau recognizes minor civil divisions in 28 states, the District of Columbia, Puerto Rico, and the Island Areas. 

A census county division (CCD) is a statistical subdivision of a county, delineated by the U.S. Census Bureau in cooperation with state and local government officials for data presentation purposes. A census county division usually represents one or more communities, trading centers or, in some instances, major land uses. The Census Bureau has established census county divisions in states that do not have minor civil divisions suitable for data presentation.  

Minor civil divisions and census county divisions together cover the entire country and provide a standard level of geography below the county. Minor civil divisions are more common in the East, while census county divisions are more common in the West.   

## Minor Civil Division /             Census County Division Map 

- Minor Civil Division /             Census County Division Map

**Notes:**
In this map, we see Taos county in New Mexico.  This map displays the census county division using the green boundary that in some areas follows along the auburn-colored census tract boundaries.  In this case the census county division divides the county into 5 areas, while there are 6 census tracts visible in this county.  Again, census tracts may be altered for each census, while census county divisions and minor civil divisions are designed to be more stable and correspond to more obvious physical boundaries.  
Maps displaying minor civil division boundaries would be set up in essentially the same way, with township, town, or district boundaries replacing the census county division boundaries.  

## Counties

- Counties in 48 States
- Independent Cities in 4 States
- Parishes in Louisiana
- Cities and Boroughs in Alaska

**Notes:**
EAST SLIDE VERSION
Counties are the primary subdivision of most states. A number of geographic entities are not legally designated as a county, but are recognized by the U.S. Census Bureau as equivalent to a county for data presentation purposes. These include the boroughs, city and boroughs, municipality, and census areas in Alaska; parishes in Louisiana; and cities that are independent of any county in Maryland, Missouri, Nevada, and Virginia.  Because they contain no primary legal divisions, the Census Bureau treats the District of Columbia and Guam each as equivalent to a county (as well as equivalent to a state) for data presentation purposes. 
The map on this slide illustrates the independent city of Baltimore in Maryland.  Notice that it is entirely surrounded by counties, in this case Baltimore County and Anne Arundel County.

Speaker Notes:  Other division recognized as county equivalents: municipios in Puerto Rico, districts and islands in American Samoa, municipalities in the Northern Mariana Islands, and islands in the Virgin Islands.  
A county is a minor civil division in American Samoa. 
City and Borough in Alaska: A legally established geographic entity in Alaska, which the U.S. Census Bureau treats as the statistical equivalent of a county in other states; also, in Alaska, a type of incorporated place. This designation is new for Census 2000.

## Counties

- Counties in 48 States
- Independent Cities in 4 States
- Parishes in Louisiana
- Cities and Boroughs in Alaska

**Notes:**
WEST SLIDE VERSION
Counties are the primary subdivision of most states. A number of geographic entities are not legally designated as a county, but are recognized by the U.S. Census Bureau as equivalent to a county for data presentation purposes. These include the boroughs and census areas in Alaska; parishes in Louisiana; and cities that are independent of any county in Maryland, Missouri, Nevada, and Virginia.  Because they contain no primary legal divisions, the Census Bureau treats the District of Columbia and Guam each as equivalent to a county (as well as equivalent to a state) for data presentation purposes. 
Here we see a reference map from American FactFinder that shows the many counties in the western portion of the U.S.

Speaker Notes:  Other division recognized as county equivalents: municipios in Puerto Rico, districts and islands in American Samoa, municipalities in the Northern Mariana Islands, and islands in the Virgin Islands.  
A county is a minor civil division in American Samoa. 
City and Borough in Alaska: A legally established geographic entity in Alaska, which the U.S. Census Bureau treats as the statistical equivalent of a county in other states; also, in Alaska, a type of incorporated place. This designation is new for Census 2000.

## Large Geographic Areas

- U.S. 		-    Metropolitan Areas
- Regions	-    Urbanized Areas
- Divisions 	-    American Indian 						Reservations
- States	-    Alaska Native Areas
- 			     Hawaiian Home Land Areas

**Notes:**
There are also larger geographic levels for which data are available; some of these are outside of any geographic hierarchy.  

## Census Regions and Divisions of the United States

**Notes:**
Everyone is familiar with the 50 States.  The District of Columbia and the Commonwealth of Puerto Rico are treated as state equivalents.  
In some Census 2000 and Economic Census products you will see data for regions and divisions.  The Census Bureau divides the Nation into four regions and nine divisions, composed of groups of states.  
Here we see a map displaying the Census regions and divisions of the United States. 
The South region is divided into the South Atlantic, East South Central, and West South Central divisions.
The Northeast region is divided into New England and the Middle Atlantic divisions.  
The Midwest region is divided into the West North Central and East North Central divisions.
The West region is divided into the Mountain and Pacific divisions.

Now we’ll take a look at Metropolitan Areas.

## Metropolitan Areas

- Defined by the Office of Management and Budget (OMB)
- Made up of a county or counties (or equivalent entities)
- Contain large population nucleus
- High socioeconomic integration

**Notes:**
The general concept of a Metropolitan Area is that of a core area containing a large population nucleus, together with adjacent communities having a high degree of economic and social integration with that core.
Currently defined Metropolitan Areas are based on application of 1990 standards to 1990 decennial census data and to subsequent Census Bureau population estimates and special census data.
The collective term ”Metropolitan Area" (MA) became effective in 1990. Metropolitan Areas include Metropolitan Statistical Areas (MSAs), Consolidated Metropolitan Statistical Areas (CMSAs), and Primary Metropolitan Statistical Areas (PMSAs). 

## Metropolitan Area: Three Types

- Metropolitan Statistical Area (MSA): One city with 50,000 or more inhabitants or a Census-defined urbanized area and a total metropolitan population of at least 100,000 (75,000 in New England)
- Consolidated Metropolitan Statistical Area (CMSA): Meets MSA standards and population > 1 million, separate standard-meeting components can be identified, and local opinion supports component areas
- Primary Metropolitan Statistical Area (PMSA): Components that make up a CMSA

**Notes:**
Under Metropolitan Area standards, the county (or counties) that contains the largest city becomes the "central county" (counties), along with any adjacent counties that have at least 50 percent of their population in the urbanized area surrounding the largest city. Additional "outlying counties" are included in the MA if they meet specified requirements of commuting to the central counties and other selected requirements of metropolitan character (such as population density and percent urban). In New England, the MAs are defined in terms of cities and towns rather than counties.
Metropolitan Statistical Areas (MSAs) are generally smaller metropolitan areas under 1,000,000 in population.  
Consolidated Metropolitan Statistical Areas (CMSAs) are large metropolitan areas such as NY, Chicago, LA, etc. that have over 1,000,000 in population.  Within CMSAs are the smaller components called Primary Metropolitan Statistical Areas (PMSAs).  For example in the Washington-Baltimore CMSA, there are three PMSAs: Washington, Baltimore, and Hagerstown. 
As of the June 30, 1999 OMB announcement detailing the 1990 MA standards, there were 258 MSAs, and 18 CMSAs comprising 73 PMSAs in the United States. In addition, there were 3 MSAs, 1 CMSA, and 3 PMSAs in Puerto Rico. 
The Office of Management and Budget (OMB) announced revised standards for metropolitan statistical areas, and a new type of entity called a micropolitan statistical area, in the Federal Register on December 27, 2000. However, the OMB will not identify the entities that are based on the new standards and Census 2000 data until mid-2003. The Census 2000 data products present information for the metropolitan areas and central cities announced by the OMB on June 30, 1999, and therefore are in effect on Census Day, April 1, 2000; these entities reflect the 1990 metropolitan area standards. 

## Metropolitan Area Map

**Notes:**
Here we see a 1999 Metropolitan Area Map for Maryland.  This map shows the Washington-Baltimore Metropolitan Area in the center as well as a part of the Philadelphia-Wilmington-Atlantic City Metropolitan Area in the upper right hand corner.  Through interpreting the legend we can see that the Washington-Baltimore Consolidated Metropolitan Statistical Area is outlined in the thickest orange line.  Within that CMSA, there are separate Primary Metropolitan Statistical Areas of Washington, Baltimore, and Hagerstown.  
You can also note that Cumberland Metropolitan Statistical Area in the upper left-hand corner (composed of 2 counties) is a MSA unto itself and is not affiliated with the Washington-Baltimore CMSA.  The MSA is labeled here in ALL CAPS, whereas the PMSAs that make up the CMSA are labeled in only initial caps.     

## Urbanized Areas

- Densely settled areas with population of at least 50,000
- Geographic core of block groups or blocks that have a population density of at least 1,000 people per square mile
- Standards currently under review
- www.census.gov/geo/www/ua/ua_2k.html

**Notes:**
The Census Bureau is currently reviewing its criteria for urban/rural delineations and will be announcing the official decision in the 2nd quarter of 2002.  
An urbanized area (UA) is a densely settled area that has a census population of at least 50,000. At least 35,000 people in an urbanized area must live in territory that is not part of one or more military reservations, or it is classified as an urban cluster. A UA generally consists of a geographic core of block groups or blocks that have a population density of at least 1,000 people per square mile, and adjacent block groups and blocks with at least 500 people per square mile. A UA may consist of all or part of one or more incorporated places and/or census designated places, and may include area adjacent to the place(s).
UAs and MAs are not synonymous. Urbanized areas are based on blocks and block groups.  Metropolitan areas include complete counties.  
For Census 2000, UA delineations constitute a zero-based approach that requires no grandfathering of UA boundaries from the 1990 census.  In a nutshell the new delineations have more stringent density requirements and less restrictive extended place criteria.

## American Indian Areas

- Tribal block groups
- Tribal census tracts
- Tribal designated statistical area

-    Reservations

**Notes:**
A block group within a tribal census tract is referred to as a tribal block group when tribes identified the areas. Where a census tract numbered in the 9400 series crosses a county line, the same tribal block group may be assigned on both sides of that boundary.
When data are provided for American Indian entities, the boundary of a federally recognized American Indian reservation and off-reservation trust land is always the boundary of a tribal census tract.  The optimum size for a tribal census tract is 2,500 people, with a minimum of 1,000 people. 
A tribal designated statistical area is a statistical entity delineated for the U.S. Census Bureau by a federally recognized American Indian tribe that does not have a federally recognized land base (a reservation or off-reservation trust land).  New for Census 2000, a tribal designated statistical area may cross a state line. For the 1990 census, tribal designated statistical areas included state-recognized tribes without a land base; these are now called state designated American Indian statistical areas. 
Federal American Indian reservations are areas with boundaries established by treaty, statute, and/or executive or court order, and, along with off-reservation trust lands, are recognized by the federal government as territory in which American Indian tribes have primary governmental authority.
In the map here we can see the American Indian area (or reservation) in light green whose boundaries are that of tribal census tract 9404.  In dark green we see various off-reservation trust lands which are contained in single blocks or groups of blocks.

## Alaska Native Areas/Hawaiian Home Land Areas 

- 12 Alaska Native Regional Corporations - cover the state
- Alaska Native Village Statistical Area (ANVSA)
- Hawaiian Home Lands

**Notes:**
Alaska Native Regional Corporations (ANRCs) are corporate entities established to conduct both business and nonprofit affairs of Alaska Natives. Alaska is divided into 12 Alaska Native Regional Corporations that cover all of the state except for the Annette Island Reserve.
The Alaska Native Village Statistical Area (ANVSA) represent the settled portion of Alaska Native villages (ANVs), which constitute tribes, bands, clans, groups, villages, communities, or associations established also as part of the Settlement Act of 1972. 
Hawaiian home lands (HHLs) are lands held in trust for Native Hawaiians by the State of Hawaii, pursuant to the Hawaiian Homes Commission Act of 1920, as amended. The U.S. Census Bureau obtained the names and boundaries of Hawaiian home lands from state officials. Hawaiian home lands are a new geographic entity for Census 2000.   These areas are defined much like American Indian reservations.
Both these types of state areas are represented on maps in a similar fashion to the way the American Indian areas are represented in the previous slide.

## American Indian Area/Alaska Native Area/Hawaiian Home Land Hierarchy

**Notes:**
Here we see the hierarchy of American Indian Areas, Alaska Native Areas, and Hawaiian Home Land Areas as they relate to other divisions and on down to the local area Block.  
The Oklahoma Tribal Statistical Areas which have not yet been mentioned, are statistical entities identified and delineated by federally recognized American Indian tribes in Oklahoma that formerly had a reservation but do not now have a reservation in that state. The boundary of an OTSA will be that of the former reservation in Oklahoma, except where modified by agreements with neighboring tribes for statistical data presentation purposes. They may cross the boundary of Oklahoma and include territory in a neighboring state but not territory in any reservation. Replaces the Tribal Jurisdiction Statistical Areas (TJSAs) of 1990.

## Special Geographic Areas

- Zip Code Tabulation Area (ZCTA)
- Congressional Districts
- Public Use Microdata Area (PUMA)

**Notes:**
Now we’ll take a look at some of the geographic units that are not easily categorized within the previous, more common frameworks.  

## ZIP Code Tabulation Areas (ZCTAs)

- Approximate area representations of USPS ZIP Code service areas
- Based on Census 2000 blocks
- To address difficulties in mapping USPS ZIP Codes
- May represent either a five or three-digit USPS ZIP Code

**Notes:**
Another new aspect of geography for Census 2000 is the ZIP Code Tabulation Area (ZCTA).  This is a new statistical area that the Census Bureau has created to address the problems associated with tabulating data by ZIP Codes.  They are generalized representations of USPS ZIP Code areas.  Since ZIP Codes are tools for delivering mail and were never intended to provide the basis for statistical tabulations, they are often not appropriate for that use.  ZIP Codes are usually just collections of streets representing a carrier route. What complicates matters is that they can be assigned to just one building, or even to a single company within a building and they are solely designed to get the mail delivered.

Zip Code Tabulation Areas can represent either five or three-digit Postal Service ZIP Codes.  There are no ZCTAs for the nine-digit ZIP Codes.

## How ZIP Code Tabulation Areas Are Created

- Determine the majority ZIP Code for each census block with addresses.

**Notes:**
To be able to provide statistical data by ZIP Codes, the Census Bureau has created the ZIP Code Tabulation Area or ZCTA to be as close an approximation to actual ZIP Code coverage as possible but also having the characteristics of other statistical areas, such as definable boundaries.  The Census Bureau uses the addresses in its Topologically Integrated Geographic Encoding and Referencing System or TIGER database and Master Address File database to determine the areas covered by each ZIP Code and uses that information to interpolate boundaries for these areas as they relate to Census 2000 blocks. This means that the Census Bureau will create Zip Code Tabulation Areas by grouping whole census blocks.  The ZIP Code used by the majority of addresses in a given block will determine the ZIP Code Tabulation Area code for that block.  While there is no legal or operational requirement for the Postal Service to abide by these boundaries the Census Bureau believes that ZIP Code Tabulation Areas will closely follow actual ZIP Code coverage.  Also note that P.O. Boxes and rural routes will not have accompanying ZIP Code Tabulation Areas.

## Public Use Microdata Areas (PUMAs)

- Geographic entity for extracts of raw data from a small sample of confidentiality-screened, long-form census records
- Minimum population of 100,000, cannot cross a state line (5-percent long-form records sample)
- Super PUMAs - Aggregated PUMAs with a minimum population of 400,000     (1-percent sample in a national file)

**Notes:**
Public Use Microdata Areas (PUMAs) are geographic entities for which the U.S. Census Bureau provides specially selected extracts of raw data from a small sample of long-form census records.  All personal identifying information has been removed from these records.  The extract files are referred to as public use microdata samples (PUMS). 
Public Use Microdata Areas must have a minimum census population of 100,000 and unlike 1990 cannot cross a state line.  A 5-percent sample of the long-form records is extracted and presented in state files.  Super-PUMAs, areas of 400,000 population, are combinations of PUMAs and represent the areas for which the Census Bureau provides a 1-percent file.
(Data users can use these files to create their own statistical tabulations and data summaries.)

Another new wrinkle for Census 2000 Public Use Microdata Areas is that the 5-percent PUMAs must nest within the 1-percent PUMAs whereas in 1990 the different sets could cover different areas.

## Geographic Hierarchy

**Notes:**
This diagram of the Census geographic hierarchy presents this information as a series of nesting relationships. For example, a line joining the lower-level entity place and the higher-level entity state means that a place cannot cross a state boundary; a line linking census tract and county means that a census tract cannot cross a county line; and so forth.  The areas on the outside of the main middle line do not necessarily follow along and have census tracts or block groups.  As you can see, they do all relate back to the most basic unit, the census block.

More data are available for the larger geographic areas, such as the states and counties.  Less data are available for smaller geographic units such as census tracts and blocks.

## Hierarchy - Summary File 1: State FileSummary Levels

- State
- 	County
- 		Place (or place part)
- 		    Census tract
- 			  Block group
-                		Block
- State portion of American Indian and Alaska Native Area (with trust lands and with no trust lands) and Hawaiian home land

**Notes:**
Using the example of the Census Bureau’s Summary File 1 (SF 1), this slide illustrates how attention must be paid to what levels of geography are included in different data products.    
Summary File 1 is released as individual files for each of the 50 states, the District of Columbia, and Puerto Rico; and for the United States. The tables are identical for all files, but the geographic coverage differs.

Summary File 1 for states, the District of Columbia, and Puerto Rico provides data for these areas and their subareas in hierarchical sequence down to the block level (census tract level for some tables). The file structure includes, but is not limited to the geographic entities shown on the slide: state, county, county subdivision, place (or place part), census tract, block group and block.
SF 1 for states also has summarized data for the following geographic areas; Place, Census tract, Block group, Congressional District (106th Congress), Consolidated city, Metropolitan area and ZIP Code tabulation area (ZCTA).

## Unique Geographic Identifiers

- Federal Information Processing Standards (FIPS) Codes
- _Area__	_	_Name__	__	__	__2000 FIPS_
- State	North Carolina 		37
- County	Transylvania		175
- Place	Wilmington 		74440

**Notes:**
To help users process information on CD-ROM, DVD, and to uniquely identify geographic areas, the Census Bureau uses a series of geographic identifiers which are generally numeric codes established by the National Institute of Standards, and known as FIPS or Federal Information Processing Standards codes.
In Census Bureau data products, you will find FIPS codes for higher level geographic units such as states, counties, places, congressional districts, etc.
The Census Bureau establishes its own set of codes as, for example, in the case of census tracts or blocks if there is no FIPS code for the geographic entity or if the FIPS codes is not adequate for data presentation.  
These codes are used for each unique geography to allow users to link their own databases to the census data.

Speaker Note: (A census code exists for each state, but was not assigned in alphabetical sequence and serves to organize the states by census region and census division.)

## Questions/Feedback

- E-mail: geography@census.gov
- URL:  www.census.gov
- General Questions: 301-457-4100
- Geographic Questions: 301-457-1128