Today’s Wyoming counties did not always exist in the present form. They went through many different changes in the space of a few short years.

Wyoming Territorial Counties

The Wyoming Territory, was organized on July 25, 1868 from the Dakota, Idaho and Utah Territories. Cheyenne was the territorial capital.

In the beginning Wyoming Territory originally had 4 counties. They were Laramie and Carter, established in 1867; Carbon and Albany established in 1868.

On May 19, 1869, the newly-organized territory added  Uinita County County from portions of Idaho and Utah that were previously unorganized. At that same time, Carter County became Sweetwater County.

The Territory of Wyoming existed until July 10, 1890. 

The State of  Wyoming was admitted to the Union as a the 44th state on July 10, 1890 with 13 counties. There were 10 more Wyoming counties were created after statehood.

Wyoming Counties Today

Today, Wyoming has 23 Counties, which were all in existence by 1923. States bordering Wyoming are ColoradoMontanaNebraska, South DakotaUtah and Idaho.

Fun Facts about Wyoming Counties

Counties by Year

County Size Facts

County Population Facts

Wyoming City Facts

Wyoming’s 10  largest cities (2019) are:

  1. Cheyenne (65,864) is in Laramie County
  2. Casper (59,171) is in Natrona County
  3. Gillette (31,783) is in Campbell County
  4. Laramie (32,715) is in Albany County
  5. Rock Springs (23,014) is in Sweetwater County
  6. Sheridan (18,071) is in Sheridan County
  7. Green River (11,777) is in Sweetwater County
  8. Evanston (11,967) is in Uinta County
  9. Riverton (11,003) is in Fremont County
  10. Jackson (10,413) is in Teton County

Map of Wyoming County Boundary Changes from 1848 to 1965

This Interactive Map of Wyoming Counties show the historical boundaries, names, organization, and attachments of every county, extinct county and unsuccessful county proposal from the creation of Wyoming from 1848-1965.

List of Wyoming Counties

List of Old Former / Extinct Wyoming Counties

At least 3 Wyoming counties that were established no longer exist. These are important for genealogy research purposes.

The below Wyoming counties no longer exist:

Carter County, Wyoming

Created on December 27, 1867 as a county within the Dakota Territory. It was formed from part of  Laramie County and named in honor of Judge W.A. Carter of Fort Bridger. It was renamed to Sweetwater County on December 13, 1869.

Hanover County County, Wyoming

Created on February 14, 1911 as a county within the Dakota Territory. It was formed from part of  Laramie County and named in honor of Judge W.A. Carter of Fort Bridger.

It was renamed to Washakie County on February 14, 1911 and named in honor of was named for the head chief of the Shoshone people, Chief Washakie.

Pease County, Wyoming

Created on December 8, 1875. It was formed from parts of AlbanyCarbon, and SweetwaterCounties and was named for Dr. E. L. Pease of Uinta County.

Pease County was renamed to Johnson County on December 13, 1879 in honor of for E. P. Johnson, a Cheyenne attorney.

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