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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.

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

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

Changes to Counties or County Equivalent Entities: 1980s

New Counties or County Equivalent Entities

  • Aleutians East Borough, Alaska (02-013):
    Created from part of the former Aleutian Islands Census Area (02-010) effective October 23, 1987. The remainder of the former Aleutian Islands Census Area was established as the new Aleutians West Census Area (02-016); 1980 population: 1,643.
  • Aleutians West Census Area, Alaska (02-016):
    Created from the remainder of the former Aleutian Islands Census Area (02-010) when the new Aleutians East Borough (02-013) was created effective October 23, 1987; 1980 population: 6,125.
  • Lake and Peninsula Borough, Alaska (02-164):
    Created from part of the Dillingham Census Area (02-070) effective April 24, 1989; 1980 population: 1,384.
  • Northwest Arctic Borough, Alaska (02-188):
    Created from all of the former Kobuk Census Area (02-140) and an unpopulated part of the North Slope Borough (02-185) effective June 2, 1986; 1980 population: 4,831.
  • La Paz County, Arizona (04-012):
    Created from part of Yuma County (04-027) effective January 1, 1983; 1980 population: 12,557.
  • Cibola County, New Mexico (35-006):
    Created from part of Valencia County (35-061) effective June 19, 1981; 1980 population: 30,347.

Deleted Counties or County Equivalent Entities

  • Aleutian Islands Census Area, Alaska (02-010):
    Split to create the Aleutians East Borough (02-013) and the Aleutians West Census Area (02-016) effective October 23, 1987.
  • Kobuk Census Area (02-140):
    All taken plus unpopulated part of the North Slope Borough (02-185) to create the new Northwest Arctic Borough (02-188) effective June 2, 1986.

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

  • DeKalb County, Alabama (01-049):
    Name corrected from De Kalb County.
  • DeSoto County, Florida (12-027):
    Name corrected from De Soto County.
  • DeKalb County, Georgia (13-089):
    Name corrected from De Kalb County.
  • DeKalb County, Illinois (17-037):
    Name corrected from De Kalb County.
  • DuPage County, Illinois (17-043):
    Name corrected from Du Page County.
  • DeSoto County, Mississippi (28-033):
    Name corrected from De Soto County.
  • DeKalb County, Missouri (29-063):
    Name corrected from De Kalb County.
  • LaMoure County, North Dakota (38-045):
    Name corrected from La Moure County.
  • DeKalb County, Tennessee (47-041):
    Name corrected from De Kalb County.
  • DeWitt County, Texas (48-123):
    Name corrected from De Witt County.

Substantial County or County Equivalent Entity Boundary Changes

  • Dillingham Census Area (02-070):
    Part taken to create the new Lake and Peninsula Borough (02-164) effective April 24, 1989; 1980 detached population: 1,384.
  • North Slope Borough (02-185):
    Unpopulated part plus all of the former Kobuk Census Area (02-140) taken to create the new Northwest Arctic Borough (02-188) effective June 2, 1986.
  • Yuma County, Arizona (04-027):
    Part taken to create new La Paz County (04-012) effective January 1, 1983; 1980 detached population: 12,557.
  • Adams County, Colorado (08-001):
    Annexed part of Denver County (08-031) coextensive with Denver city effective October 18, 1980; estimated population: 2,500. Part annexed to Denver County (08-031) effective May 17, 1988; estimated area 43.31 square miles with no estimated population.
  • Denver County, Colorado (08-031) coextensive with Denver city:
    Part annexed to Adams County (08-001) effective October 18, 1980; estimated population: 2,500. Annexed part of Adams County (08-001) effective May 17, 1988; estimated area 43.31 square miles with no estimated population. Part annexed to Arapahoe County (08-005) effective July 28, 1980; estimated area one square mile with no estimated population.
  • Arapahoe County, Colorado (08-005):
    Annexed part of Denver County (08-031) coextensive with Denver city effective July 28, 1980; estimated area one square mile with no estimated population.
  • Valencia County, New Mexico (35-061):
    Part taken to create new Cibola County (35-006) effective June 19, 1981; 1980 detached population: 30,347.
  • Albemarle County, Virginia (51-003):
    Part annexed to Charlottesville (independent) city (51-540) effective February 9, 1988; no estimated population available.
  • Augusta County, Virginia (51-015):
    Part annexed to Staunton (independent) city (51-790) effective December 31, 1986; estimated population: 2,300. Part annexed to Waynesboro (independent) city (51-820) effective December 31, 1985; estimated population 3,000.
  • Fairfax County, Virginia (51-059):
    Part annexed to Fairfax (independent) city (51-600) effective December 31, 1980; estimated population: 1,100.
  • Greensville County, Virginia (51-081):
    Part annexed to Emporia (independent) city (51-595) effective January 1, 1988; estimated population: 400.
  • James City County, Virginia (51-095):
    Part annexed to Williamsburg (independent) city (51-830) effective January 1, 1983; estimated population: 400.
  • Pittsylvania County, Virginia (51-143):
    Part annexed to Danville (independent) city (51-590) effective December 31, 1987 and December 31, 1988; estimated population: 10,500.
  • Prince William County, Virginia (51-153):
    Part annexed to Manassas (independent) city (51-683) effective December 31, 1983; estimated population: 300.
  • Rockbridge County, Virginia (51-163):
    Part annexed to Buena Vista (independent) city (51-530) effective December 31, 1983; estimated population: 200.
  • Rockingham County, Virginia (51-165):
    Part annexed to Harrisonburg (independent) city (51-660) effective December 31, 1982; estimated population: 5,500.
  • Southampton County, Virginia (51-175):
    Part annexed to Franklin (independent) city (51-620) effective December 31, 1985; estimated population: 600.
  • Spotsylvania County, Virginia (51-177):
    Part annexed to Fredericksburg (independent) city (51-630) effective December 31, 1983; estimated population: 2,800.
  • Buena Vista (independent) city, Virginia (51-530):
    Annexed part of Rockbridge County (51-163) effective December 31, 1983; estimated population: 200.
  • Charlottesville (independent) city, Virginia (51-540):
    Annexed part of Albemarle County (51-003) effective February 9, 1988; no estimated population available.
  • Danville (independent) city, Virginia (51-590):
    Annexed part of Pittsylvania County (51-143) effective December 31, 1987 and December 31, 1988; estimated population: 10,500.
  • Emporia (independent) city, Virginia (51-595):
    Annexed part of Greensville County (51-081) effective January 1, 1988; estimated population: 400.
  • Fairfax (independent) city, Virginia (51-600):
    Annexed part of Fairfax County (51-059) effective December 31, 1980; estimated population: 1,100.
  • Franklin (independent) city, Virginia (51-620):
    Annexed part of Southampton County (51-175) effective December 31, 1985; estimated population: 600.
  • Fredericksburg (independent) city, Virginia (51-630):
    Annexed part of Spotsylvania County (51-177) effective December 31, 1983; estimated population: 2,800.
  • Harrisonburg (independent) city, Virginia (51-660):
    Annexed part of Rockingham County (51-165) effective December 31, 1982; estimated population: 5,500.
  • Manassas (independent) city, Virginia (51-683):
    Annexed part of Prince William County (51-153) effective December 31, 1983; estimated population: 300.
  • Staunton (independent) city, Virginia (51-790):
    Annexed part of Augusta County (51-015) effective December 31, 1986; estimated population: 2,300.
  • Waynesboro (independent) city, Virginia (51-820):
    Annexed part of Augusta County (51-015) effective December 31, 1985; estimated population: 3,000.
  • Williamsburg (independent) city, Virginia (51-830):
    Annexed part of James City County (51-095) effective December 31, 1983; estimated population: 400.

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