Wyoming license plate numbers begin with a prefix number that designates the county in which the vehicle is registered.
Phil Roberts, Professor of History Emeritus at the University of Wyoming, said that the Wyoming counties' numbers were based on land valuation at the time the system was developed in the 1930s.
For example, Laramie Country, the home of the city of Cheyenne, is number 2; and Albany Country, home of the city of Laramie is number 5. There are 23 counties in Wyoming, so each of our vehicles' plates most likely starts with one of those numbers.
The number on the far left of the license plate represents the county from which the plate was issued. The numbers were assigned to counties according to their total county property valuation.
The numbering system dates back to the 1930s. Before that, the state-issued license numbers. In 1913 the state saw the first law requiring plates, in the decade prior there had been no requirement. In 1930 the responsibility of issuing plates was given to the counties, that was when the number of assignments began. In 1936 the new plats became standard.