History and Facts of Wyoming Counties
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.
In the beginning Wyoming Territory originally had 4 counties. They were Laramie and Carter, established in 1867; Carbon and Albany established in 1868.
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.
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
|County||Created||Created From||Named For||County Seat||Notes|
|Albany County||16 Dec 1868||One of the original five counties||Laramie|
|Big Horn County||12 Mar 1890||Sheridan County, Johnson County, and Fremont County||Basin|
|Campbell County||13 Feb 1911||Weston County and Crook County||Gillette|
|Carbon County||16 Dec 1868||One of the original five counties.||Rawlins|
|Converse County||09 Mar 1888||Albany County and Laramie County||Douglas|
|Crook County||08 Dec 1875||Laramie County and Albany County||Sundance|
|Fremont County||05 Mar 1884||Sweetwater County||Lander|
|Goshen County||09 Feb 1911||Laramie County||Torrington|
|Hot Springs County||09 Feb 1911||Fremont County, Big Horn County, and Park County||Thermopolis|
|Johnson County||13 Dec 1869||Carbon County and Sweetwater County||Buffalo|
|Laramie County||09 Jan 1867||One of the original five counties||Cheyenne|
|Lincoln County||20 Feb 1911||Uinta County||Kemmerer|
|Natrona County||09 Mar 1888||Carbon County||Casper|
|Niobrara County||14 Feb 1911||Converse County||Lusk|
|Park County||15 Feb 1909||Big Horn County||Cody|
|Platte County||09 Feb 1911||Laramie County||Wheatland|
|Sheridan County||09 Mar 1888||Johnson County||Sheridan|
|Sublette County||15 Jan 1921||Fremont County and Lincoln County||Pinedale|
|Sweetwater County||27 Dec 1867||One of the original five counties||Green River|
|Teton County||15 Feb 1921||Lincoln County||Jackson|
|Uinta County||01 Dec 1869||One of the original five counties||Evanston|
|Washakie County||09 Feb 1911||Big Horn County||Worland|
|Weston County||12 Mar 1890||Crook County||Newcastle|
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.
Pease County, Wyoming
Pease County was renamed to Johnson County on December 13, 1879 in honor of for E. P. Johnson, a Cheyenne attorney.