In 1945, Idaho began using the county license plate prefix designators still in use today. If you know the system, you can identify the county that issued most Idaho plates.
How Idaho's System Works
You can memorize Idaho's license plate codes by arranging the 44 counties alphabetically.
- When a single county begins with a given letter (like Nez Perce County, for example), it's code is that letter ("N" in this example).
- When two or more counties begin with the same letter, number the counties (maintaining their alphabetical order). Then place the number before their initial letter. Thus, Ada County's license plate code is "1A"; Adams County's code is "2A". The codes for the 10 "B" counties start with "1B" (for Bannock) and end with "10B" (for Butte).