List of counties in Wyoming
There are 23 counties in the U.S. state of Wyoming. There were originally five counties in the Wyoming Territory: Laramie and Carter, established in 1867; Carbon and Albany established in 1868; and Uinta, an annexed portion of Utah and Idaho, extending from Montana (including Yellowstone Park) to the Wyoming–Utah boundary.
Source: Wikipedia — List of counties in Wyoming (CC BY-SA 4.0)