Geography - Census - Decennial - LibGuides Home at Connecticut State Library.

Census Geography

It is important to understand geography concepts used in the censuses - especially for New England. And the terms and concepts have changed over time. Sometimes looking at instructions for a specific census might help (links in the Quick Link box on the left).

As the Census Bureau says: "Geography plays an important role in Census Bureau activities, including supporting the American Community Survey. It is the framework by which the Census Bureau collects and publishes demographic, social, housing, and economic data. Geography contributes to, and is involved in, ACS sampling, data collection, weighting, and data tabulation activities."

Here are some links to help with geography used in the censuses.

Guidance for Geography Users (Census)
Site: "In this section you will find information to help you understand the products and references found in other sections. We describe the what, why, and how of Census geography."
Concept & Definitions (Census)
From site: "Geography plays an important role in Census Bureau activities, including supporting the American Community Survey. It is the framework by which the Census Bureau collects and publishes demographic, social, housing, and economic data. Geography contributes to, and is involved in, ACS sampling, data collection, weighting, and data tabulation activities." Topics include: Areas; Hierarchy; Area Codes; Change; Definitions
Geography and the American Community Survey. What Data Users Need to Know
Issued February 2020
Census Geography for the American Community Survey (ACS)
Census Regions and Divisions of the United States
Map of the Regions and Divisions
Hierarchy Diagrams (Census)
Site: "The standard hierarchy of census geographic entities displays the relationships between legal, administrative, and statistical boundaries maintained by the U.S. Census Bureau. The hierarchy provides a quick and easy way to see how the different geographic entities at the Census Bureau relate to one another. In other words, it shows how different geographic areas may, or may not, be related. It depicts relationships with a line and shows where relationships do not exist by displaying entities on different line tracts."
Geographic Areas Reference Manual (GARM) (Census)
Essential for 1990 forward. Site: "The Geographic Areas Reference Manual (GARM) describes in great detail the basic geographic entities the Census Bureau used in its various data tabulations for the 1990 Census and documents the purposes, definitions, standards, criteria, and procedures used to select, define, delineate, and revise those geographic entities."
TIGER Data Products Guide
Census Bureau chart to help select what to use.
DATA GEMS: What is a CDP? Making Sense of Census Geography
Census Bureau video explanation
Geography Program (Census)
Site: "Geography is central to the work of the Census Bureau, providing the framework for survey design, sample selection, data collection, tabulation, and dissemination. Geography provides meaning and context to statistical data."
Migration/Geographic Mobility - About (Census)
Site: "Migration and geographic mobility both refer to the movement of people from one location to another. Migration typically refers to moves that cross a boundary, such as a county or state line, and is either domestic migration (movement within the U.S.) or international migration (movement between the U.S. and other countries). Mobility includes both short and long-distance moves."
New England City and Town Areas Map (September 2018) (Census)
Site: The "New England City and Town Areas" wall map shows metropolitan and micropolitan New England city and town areas (NECTAs), combined NECTAs, and metropolitan NECTA divisions, and identifies their components in six New England states: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. The boundaries and names depicted reflect the September 2018 definitions described by the U.S. Office of Management and Budget.
Reference Maps (Census)
Site: Reference maps show the boundaries and names of geographic areas for which the Census Bureau tabulates statistical data, but do not visualize the data.
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Site: In some cases, the name is only in the form of a geographic code, such as a census block number. Some types of reference maps show and identify geographic features that are part of the boundary. Examples are roads and water features.
Reference maps can include additional features such as railroads to aid users in orienting themselves to a place on the map.
UNC Research Guide on Census Geography
Includes a diagram to visualize the hierarchy of census geography.
DATA GEMS: What is a Census Tract? Making Sense of Census Geography
Census Bureau video on census tracts
What Are Census Blocks?
Census Bureau page explaining census blocks
Know Your Geographies (Census)
University of Virginia page explaining census geography - highlighting hierarchical and non-hierarchical geographies.
Geography - Sacramento State
Sacramento State guide on Census geography.
Geographic Codes (Census)
Links to various Census geographic codes.
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Census Bureau: "The Census Bureau creates and maintains geographic codes for many statistical geographic areas that are not covered by FIPS codes and GNIS codes. These geographic areas include census divisions, census regions, census tracts, block groups, census blocks and urban areas."
About Geographic Areas (Census)
"Detailed current and historical definitions, delineation information, lists and data files, and links to other products related to selected types of geography."

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