In 1936, the state of Montana began using the license plate prefix numbers still used today. Numbers were assigned to counties based on their population. If you know the code number, you can identify the county that issued most Montana plates.
Montana PlateFinder was created to help you learn about Montana by reading the codes at the beginning of license plates you encounter while traveling in Montana and elsewhere. The app shows where each county is located, with links links to additional information about each county and its county seat.