There have been changes in the county and county equivalent inventory since Census 2000. These changes affect other Census geography such as census tracts. ACS data users should be aware of these issues.

Clifton Forge, Virginia

In July of 2001, the independent city of Clifton Forge changed its status to become Clifton Forge town and ceased being a county equivalent. It's former FIPS 6-4 county code (560) is no longer used. Clifton Forge town is an incorporated place within Alleghany County, Virginia, and uses FIPS 55 code (17440) and ANSI Code (02390804). In the former county equivalent Clifton Forge, the only Census 2000 tract was 701. Tract 701 retains its geographic definition, coextensive with Clifton Forge town, in the current context. However, data users wishing to access ACS 5-year estimates for this tract through AFF will need to access tract 701 through Alleghany County, Virginia (51005), instead of through the defunct Clifton Forge county equivalent (51560) as in Census 2000.

Broomfield County, Colorado

In November of 2001, Broomfield County was created from portions of Adams, Boulder, Jefferson and Weld counties in Colorado. Broomfield County is coextensive with Broomfield city, Colorado. Broomfield County uses FIPS 6-4 county code (014), and is uniquely identified by FIPS state/county code (08014).

As a result of the creation of Broomfield County from Adams, Boulder, Jefferson and Weld counties, some of the Census 2000 tracts in these counties are now wholly or partially contained in Broomfield County. The following Census 2000 tracts are now wholly contained in Broomfield County, and ACS 5-year estimates can only be accessed in AFF through Broomfield County (08014).

Tracts 85.15 and 85.16, formerly in Adams County; Tracts 131.08, 131.09, 131.10 and 131.11, formerly in Boulder County.

The remaining Census 2000 tracts that were split by the creation of Broomfield County are partially contained Broomfield and partially contained in one of the other counties. Each portion of the split Census 2000 tracts retains its original tract identifier, but its geographic definition is distinct within each current county. For example, ACS 5-year estimates for the Broomfield County portion of a split Census 2000 tract is for the Broomfield County portion only, and is in effect its own unique tract. In order to compare ACS 5-year estimates for tracts to Census 2000 tract data for this area, the user must unite the ACS estimates for each portion of the split tracts, using the same tract identifier. The following Census 2000 tracts are partially contained in Broomfield County, with its matching portion county.

Tracts 85.20, 85.27 and 85.28, split with Adams County; Tracts 129.06, 129.08, 131.04, 131.06 and 131.07, split with Boulder County; Tracts 98.22, 98.25 and 98.26, split with Jefferson County; Tracts 20.02 and 20.03, split with Weld County. ACS 5-year estimates for both portions of split tracts must be accessed in AFF through each county separately.

Alaska

Skagway Municipality

In June of 2007, the former Skagway city portion of the former Skagway-Hoonah-Angoon Census Area consolidated into the county equivalent Skagway Municipality. Skagway Municipality uses FIPS 6-4 county code (230), and is uniquely identified by FIPS state/county code (02230).

Hoonah-Angoon Census Area

In June of 2007, the former Skagway-Hoonah-Angoon Census Area was reconstituted as the Hoonah-Angoon Census Area when Skagway city consolidated into the Skagway Municipality county equivalent. The former Skagway-Hoonah-Angoon Census Area FIPS 6-4 county code (232) is no longer used. The successor Hoonah-Angoon Census Area uses FIPS 6-4 county code (105), and is uniquely identified by FIPS state/county code (02105).

Wrangell City and Borough

In June of 2008, the former Wrangell city portion of the Wrangell-Petersburg Census Area organized into Wrangell City and Borough, a county equivalent. In addition to the organizational status change, there are some small additions and minor corrections to the Wrangell City and Borough extent from the former Prince of Wales - Outer Ketchikan Census Area as a result of legal boundary changes. Wrangell City and Borough uses FIPS 6-4 county code (275), and is uniquely identified by FIPS state/county code (02275).

Petersburg Census Area

In June of 2008, the former Wrangell-Petersburg Census Area was reconstituted as the Petersburg Census Area when Wrangell city organized into Wrangell City and Borough county equivalent. The former Wrangell-Petersburg Census Area FIPS 6-4 county code (280) is no longer used. The successor Petersburg Census Area uses FIPS 6-4 county code (195), and is uniquely identified by FIPS state/county code (02195).

Ketchikan Gateway Borough

In May of 2008, Ketchikan Gateway Borough annexed a significant portion of the former Prince of Wales - Outer Ketchikan Census Area. Its extent is significantly larger, and its legal boundaries are substantially different.

Prince of Wales - Hyder Census Area

In May of 2008, resulting from the annexation of significant territory by Ketchikan Gateway Borough, the remainder of the former Prince of Wales - Outer Ketchikan Census Area was renamed Prince of Wales - Hyder Census Area. The former Prince of Wales - Outer Ketchikan Census Area FIPS 6-4 county code (201) is no longer used. The successor Prince of Wales - Hyder Census Area uses FIPS 6-4 county code (198), and is uniquely identified by FIPS state/county code (02198).

Skagway Municipality and Hoonah-Angoon Census Area

There is no change to Census 2000 tract definitions in Skagway Municipality and Hoonah-Angoon Census Area, but ACS 5-year estimates for tracts are now accessed through the Skagway Municipality and Hoonah-Angoon Census Area county equivalents in AFF, as opposed to the former Skagway-Hoonah-Angoon Census Area in Census 2000. Tract 1 is accessed through Skagway Municipality, and Tracts 2 and 3 are accessed through Hoonah-Angoon Census Area.

Wrangell City and Borough and Petersburg Census Area

There is no change to Census 2000 tract definitions in the Petersburg Census Area, and only minor changes to the geographic definition of Tract 3 in Wrangell City and Borough, due to small additions and minor corrections to legal boundaries with the former Prince of Wales - Outer Ketchikan Census Area. However, ACS 5-year estimates for tracts are now accessed through the Wrangell City and Borough and Petersburg Census Area county equivalents in AFF, as opposed to the former Wrangell-Petersburg Census Area in Census 2000. Tracts 1 and 2 are accessed through Petersburg Census Area, and Tract 3 is accessed through Wrangell City and Borough.

Ketchikan Gateway Borough and Prince of Wales - Hyder Census Area

There are major changes to the geographic definitions for two of the Census 2000 tracts in Ketchikan Gateway Borough and Prince of Wales - Hyder Census Area, resulting from the substantial annexation of territory by Ketchikan Gateway Borough from the former Prince of Wales - Outer Ketchikan Census Area. However, the remaining Census 2000 tract definitions in these areas are unchanged. The following describes the comparability of Census 2000 tract definitions in the current context, compared to their original definitions in Census 2000.

Tracts 1, 2 and 4 in Prince of Wales - Hyder Census Area have the same definitions as Tracts 1, 2 and 4 in the former Prince of Wales - Outer Ketchikan Census Area from Census 2000.

There are substantial changes in the geographic definition of Tract 3 in Prince of Wales - Hyder Census Area, and there is no comparability with Tract 3 in the former Prince of Wales - Outer Ketchikan Census Area from Census 2000. Tracts 2, 3 and 4 in Ketchikan Gateway Borough retain the same Census 2000 tract definitions.

There are substantial changes in the geographic definition of Tract 1 in Ketchikan Gateway Borough, and there is no comparability with the original Census 2000 definition of Tract 1 in Ketchikan Gateway Borough.

Lastly, AFF access to ACS 5-year estimates for Tracts 1, 2, 3 and 4 in the former Prince of Wales - Outer Ketchikan Census Area are accessed through the successor Prince of Wales - Hyder Census Area instead.

Geographies with duplicate names occur for several types of geographic areas across several summary levels. There are a total of 190 geographic areas associated with the 2005-2009 ACS 5-year data release that have duplicate names. Although these areas have duplicate names, their geographic identification codes identify them uniquely.

Type of Areas with Duplicate Names

• Elementary and Unified School Districts (across the nation)
• State Legislative Districts that are not defined (State Senate and State House Districts not defined) for water bodies in Maryland
• 2 Hawaiian Home Lands
• 4 Census Designated Places in American Indian Areas
• 2 Off-Reservation Trust Lands for the Fallon Paiute-Shoshone Tribe

The table below has been created to assist in identifying these geographic areas.

In order to use this table to identify these areas while viewing ACS 5-year data in American FactFinder, you need to select Options and Show Geographic Identifiers to display the geographic codes.

If you download ACS 5-year data for these areas, you will need to reference the geographic codes in the geographic header included in downloads.

Census tracts and block groups used to tabulate and present 2005-2009 ACS 5-year estimates are those defined for Census 2000. However, in 19 counties from 8 different states, many of the census tracts and block groups used to tabulate and present the 2005-2009 ACS 5-year estimates are either those submitted to the Census Bureau for the 2010 Census, or a preliminary version of 2010 Census definitions. These census tracts and block groups were inadvertently included in the version of the Census Bureau's geographic database (TIGER) used to produce geographic area information for the 2005-2009 ACS 5-year estimates.

The effect on the 2005-2009 ACS 5-year estimates for tracts and block groups in these counties is that the geographic definitions, tract identifiers (numbers) and/or block group identifiers (numbers) represent one of several possible states between their Census 2000 and 2010 Census definition. In some cases it is an interim state that is neither the Census 2000 nor the 2010 Census definition.

The spreadsheets document the census tracts and block groups that used geographic definitions and/or identifiers (numbers) in the 2005-2009 ACS 5-year estimates did not match those for Census 2000. The spreadsheets do not list all Census 2000 tracts and block groups in the 19 counties. The 2005-2009 ACS tracts and block groups whose geographic definitions and geographic identifiers are the same as their Census 2000 definitions and identifiers are not included on the lists.

The spreadsheets include 2010 vintage as a comparison in each list, because in many cases the 2005-2009 ACS definitions and identifiers for tracts and block groups on each list is the same as the 2010 geographic definitions and geographic identifiers (or is the 2010 definition with a different identifier). The purpose of inclusion is to identify the tracts and block groups where this condition is true, and acknowledge that in some cases comparisons to Census 2000 tracts and block groups is not possible.

Census tract spreadsheet for the following affected counties: Bibb, AL; Cass, IA; Clay, IA; Dickinson, IA; Dubuque, IA; Emmet, IA; Sioux, IA; Union, IA; Worth, IA; Calvert, MD; Berkshire, MA; Baraga, MI; Murray, MN; and Wilson, TX.

Block group spreadsheet for the following affected counties: Bibb, AL; Coles, IL; Adair, IA; Adams, IA; Cass, IA; Clay, IA; Dickinson, IA; Dubuque, IA; Emmet, IA; Madison, IA; Page, IA; Sioux, IA; Union, IA; Worth, IA; Calvert, MD; Berkshire, MA; Baraga, MI; Murray, MN; and Wilson, TX.