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Geographic Boundary Change Notes

The Geographic Change Notes provide an online resource for selected geographic changes to incorporated places, census designated places, county subdivisions, counties and equivalent areas, and American Indian, Alaska Native, and Native Hawaiian areas as recognized by the U.S. Census Bureau, within the 50 States, the District of Columbia, Puerto Rico, and the Island Areas (American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the U.S. Virgin Islands). Note that most of the census designated places (CDPs) newly defined for the 2010 Census and changes affecting the 2010 CDPs are not included in the change notes. Use the Geographic Relationship File - 2010 to 2000 Places to determine changes affecting 2010 CDPs.

For a list of updates processed through January 1, 2013, please select a state or territory from the menu below. More information about the Geographic Boundary Change Notes can be found in the sections beneath the menu.

In this section:

Types of Changes Included

Types of changes found on this website include:

  • new entities;
  • deleted entities;
  • changes in higher-level geographic relationships (state, county, and county subdivision levels);
  • mergers or consolidations of two or more entities;
  • name changes and corrections;
  • legal or statistical area description changes;
  • functional status changes;
  • changes in status of incorporated places as either dependent within or independent of surrounding county subdivisions;
  • county redistricting, that is boundary updates to nonfunctioning county subdivisions within a county;
  • National Standard code changes and corrections; and
  • Federal Information Processing Series (FIPS) code changes and corrections.

Change records (except for American Indian, Alaska Native, and Native Hawaiian areas) are listed in alphabetical sequence by entity name within each state. Each entity has a unique code combination. In addition to the state and entity codes, the record for each entity contains several related items of information for that entity and the change affecting it.

County and Equivalent Area

Each county is assigned a 3-digit code that is unique within state.   These codes are assigned alphabetically starting with 001 (except in South Dakota, where code 001 is reserved for the former Armstrong County).   For example, Autauga County, Alabama, is assigned a code of 001 in the Alabama file; Montgomery County, Maryland, is assigned a code of 031 in the Maryland file.

The independent cities of Baltimore, Maryland; St. Louis, Missouri; Carson City, Nevada; and the 39 independent cities in Virginia are independent of any county and, thus, constitute primary divisions of their states.  As such, independent cities are treated as county equivalents.   Codes for the independent cities are assigned alphabetically beginning at 500.   Data shown for the independent city at the place and county subdivision level are identical to the data for its county equivalent.

County Subdivision Area

Each county subdivision is assigned a 5-digit Federal Information Processing Series (FIPS) code.   For example, Alamo, in Montgomery County, Arkansas is assigned code 90013.

Incorporated Place, Consolidated City, and Census Designated Place (Entity Type = P)

Each place is assigned a 5-digit Federal Information Processing Series (FIPS) code. For example, Munford city, Tennessee is assigned code 51540.

In some states, places are independent (an independent place) of any surrounding county subdivision and each county-part is treated as a separate county subdivision. This is true for all incorporated places in the District of Columbia, Maine, Massachusetts, New Hampshire, New Jersey, North Dakota, Pennsylvania, Rhode Island, South Dakota, and Wisconsin and some incorporated places in 14 additional states. In these cases, the name and codes for the county subdivision match that for the incorporated place. For example, Chicago city, Illinois, is independent of any surrounding township and is shown as two county subdivisions named Chicago city with the same codes in Cook and DuPage counties.

Data Included for Each Entity

Information provided for each entity includes: state FIPS code; area name; FIPS codes; name and code of each county in which the entity is located (applies only to place and county subdivisions); type of change that occurred, the legal effective date of change; the legal effective year of change; the legal effective month of change; the legal effective day of change; detailed description of the change; the source from which the information was obtained, and the date the change was submitted to the Census Bureau's geographic change note database. Note: Neither the effective date nor the submittal date can be used to always determine when a change was applied to the geographic database or to determine the yearly product first showing the change.

File Format


These ASCII pipe-delimited files are first sequenced in numerical order based on the FIPS state codes; that is, the states and the District of Columbia occur first in numeric sequence, followed by Puerto Rico and the Outlying Areas.   Within state, the files are sequenced alphabetically by entity name.


Also available are the Geography Notes and Errata from the 2010 Census. This document contains notes on changes to Boundary and Geographic Relationships, Names and Legal/Statistical Areas, FIPS Codes, FIPS Class Codes, and ANSI Codes to correct errors discovered after the 2010 Census.

Related Information

Page Last Revised - January 18, 2022
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