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Substantial Changes to Counties and County Equivalent Entities: 1970-Present

Substantial county boundary changes are those affecting an estimated population of 200 or more; changes of at least one square mile where an estimated population number was not available, but research indicated that 200 or more people may have been affected; and annexations of unpopulated territory of at least 10 square miles.

The Census Bureau’s reference date for geographic entity boundaries in all geographic and statistical data products is January 1 of the reference year (e.g., January 1, 2019).  Boundary changes with effective dates after January 1 will appear in geographic and statistical data products referenced to the following year. For example, a change with an effective date of January 2, 2019 will appear in products referenced to 2020.

Changes are listed below in the decade they occurred.

The Census Bureau does not produce before-and-after maps illustrating the boundary changes. Contact the state or county governments for more specific information about these changes.

2000
  • 2020
  • 2010
  • 2000
  • 1990
  • 1980
  • 1970
2000

Substantial Changes to Counties and County Equivalent Entities: 1970-Present

Changes to Counties or County Equivalent Entities: 2000s

New Counties or County Equivalent Entities

  • Hoonah-Angoon Census Area, Alaska (02-105):
    Created from the remainder of the former Skagway-Hoonah-Angoon Census Area (02-232) when the new Skagway Municipality (02-230) was created effective June 20, 2007; population: 2,574.
  • Petersburg Census Area, Alaska (02-195):
    Created from the remainder of the former Wrangell-Petersburg Census Area (02-280) when the new Wrangell City and Borough was created effective June 1, 2008; estimated population: 4,260.
  • Prince of Wales-Hyder Census Area, Alaska (02-198):
    Created from the remainder of the former Prince of Wales-Outer Ketchikan Census Area (02-201) after part (Outer Ketchikan area) was annexed by Ketchikan Gateway Borough (02-130) effective May 19, 2008, and part (Meyers Chuck area) included in the new Wrangell City and Borough effective June 1, 2008; estimated population: 6,115.
  • Skagway Municipality, Alaska (02-230):
    Created from part of the former Skagway-Hoonah-Angoon Census Area (02-232) effective June 20, 2007; boundaries are identical to Skagway census subarea; population: 862. The remainder of the former Skagway-Hoonah-Angoon Census Area was established as the new Hoonah-Angoon Census Area (02-105).
  • Wrangell City and Borough, Alaska (02-275):
    Created from part of the former Wrangell-Petersburg Census Area (02-280) and part of Prince of Wales-Outer Ketchikan Census Area (02-201) (Meyers Chuck area) effective June 1, 2008; estimated population: 2,448. The remainder of the former Wrangell-Petersburg Census Area was established as the new Petersburg Census Area (02-195) effective June 1, 2008.
  • Broomfield County, Colorado (08-014):
    Created from parts of Adams (08-001), Boulder (08-013), Jefferson (08-059), and Weld (08-123) counties effective November 15, 2001. The boundaries of Broomfield County reflect the boundaries of Broomfield city legally in effect on that date; estimated population: 39,177.

Deleted Counties or County Equivalent Entities

  • Prince of Wales-Outer Ketchikan Census Area, Alaska (02-201):
    Part (Outer Ketchikan area) annexed by Ketchikan Gateway Borough (02-130) and part (Meyers Chuck area) included in new Wrangell City and Borough (02-275), remainder renamed Prince of Wales-Hyder Census Area (02-198) effective May 19, 2008.
  • Skagway-Hoonah-Angoon Census Area, Alaska (02-232):
    Split to create Skagway Municipality (02-230) and Hoonah-Angoon Census Area (02-105), effective June 20, 2007.
  • Wrangell-Petersburg Census Area, Alaska (02-280):
    Split to create part of Wrangell City and Borough (02-275) and all of Petersburg Census Area (02-195), effective June 1, 2008.
  • Clifton Forge (independent) city, Virginia (51-560):
    Changed to town status and added to Alleghany County (51-005) effective July 1, 2001.

Name and/or Code Changes or Corrections for Counties or County Equivalent Entities

  • LaSalle County, Illinois (17-099);
    Name corrected from La Salle County (removing space).
  • Doña Ana County, New Mexico (35-013):
    Name corrected from Dona Ana County (added tilde).

Substantial County or County Equivalent Boundary Changes

  • Ketchikan Gateway Borough, Alaska (02-130):
    Annexed a substantial portion of the former Prince of Wales-Outer Ketchikan Census Area (02-201), including most of the area known as Outer Ketchikan effective May 19, 2008; estimated added population: 7. As a result, the remaining area of the former Prince of Wales-Outer Ketchikan Census Area was renamed Prince of Wales-Hyder Census Area (02-198).
  • Adams County, Colorado (08-001):
    Part taken to create new Broomfield County (08-014) effective November 15, 2001; estimated detached population: 15,870.
  • Boulder County, Colorado (08-013):
    Part taken to create new Broomfield County (08-014) effective November 15, 2001; estimated detached population: 21,512.
  • Jefferson County, Colorado (08-059):
    Part taken to create new Broomfield County (08-014) effective November 15, 2001; estimated detached population: 1,726.
  • Weld County, Colorado (08-123):
    Part taken to create new Broomfield County (08-014) effective November 15, 2001; estimated detached population: 69.
  • Alleghany County, Virginia (51-005):
    Added the former independent city of Clifton Forge (51-560) effective July 1, 2001; estimated added population: 4,289.
  • York County, Virginia (51-199):
    Exchanged territory with Newport News (independent) city (51-700) effective July 1, 2007; estimated net detached population: 293.
  • Newport News (independent) city, Virginia (51-700):
    Exchanged territory with York County (51-199) effective July 1, 2007; estimated net added population: 293.

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