| WY State Facts |
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| Territory: Jul 25, 1868 |
| Statehood: Jul 10, 1890 |
| Counties: 23 |
| Borders: CO, MT, NE, SD, UT and ID |
| WY Resources |
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| WY Maps & Atlases |
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WY Military Databases |
| WY Record Collections |
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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 Colorado, Montana, Nebraska, South Dakota, Utah and Idaho.
Fun Facts about Wyoming Counties
Counties by Year
- Laramie County was the first county created on January 9, 1867.
- Sublette County (organized in 1923) and Teton County (organized in 1922) was last counties to be formed on February 15, 1921.
County Size Facts
- Sweetwater County (10,426 sq mi) is the largest county in Wyoming.
- Hot Springs County (2,004 sq mi) is the smallest county in Wyoming.
County Population Facts
- Laramie County (94,483) is the most populated county in Wyoming.
- Niobrara County (2,456) is the least populated county in Wyoming.
Wyoming City Facts
Wyoming’s 10 largest cities (2019) are:
- Cheyenne (65,864) is in Laramie County
- Casper (59,171) is in Natrona County
- Gillette (31,783) is in Campbell County
- Laramie (32,715) is in Albany County
- Rock Springs (23,014) is in Sweetwater County
- Sheridan (18,071) is in Sheridan County
- Green River (11,777) is in Sweetwater County
- Evanston (11,967) is in Uinta County
- Riverton (11,003) is in Fremont County
- 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 Albany, Carbon, 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.