The Mysterious Idaho License Plate Pattern

Idaho License Plates

Are you curious why Idaho license plates have a number followed by a letter at the beginning? You are not alone. Many Idahoans and visitors to the state have asked this question, and we are here to provide you with a detailed answer.


The license plate pattern that begins with a number followed by a letter is unique to Idaho and it has been used in the state since 1945. The purpose of this format is to make Idaho license plates easily identifiable and distinguishable from other states' license plates.


The number letter format consists of a number followed by a letter that represents the county where the vehicle is registered. There are 44 counties in Idaho, and each county is assigned a unique letter. The list of counties and their corresponding letters is as follows:


1A Ada (Boise)

2A Adams (Council)

1B Bannock (Pocatello)

2B Bear Lake (Paris)

3B Benewah (St. Maries)

4B Bingham (Blackfoot)

5B Blaine (Hailey)

6B Boise (Idaho City)

7B Bonner (Sandpoint)

8B Bonneville (Idaho Falls)

9B Boundary (Bonners Ferry)

10B Butte (Arco)

1C Camas (Fairfield)

2C Canyon (Caldwell)

3C Caribou (Soda Springs)

4C Cassia (Burley)

5C Clark (Dubois)

6C Clearwater (Orofino)

7C Custer (Challis)

E Elmore (Mountain Home)

1F Franklin (Preston)

2F Fremont (St. Anthony)

1G Gem (Emmett)

2G Gooding (Gooding)

I Idaho (Grangeville)

1J Jefferson (Rigby)

2J Jerome (Jerome)

K Kootenai (Coeur d’Alene)

1L Latah (Moscow)

2L Lemhi (Salmon)

3L Lewis (Nez Perce)

4L  Lincoln (Shoshone)

1M Madison (Rexburg)

2M Minidoka (Rupert)

N Nez Perce (Lewiston)

1O Oneida (Malad City)

2O  Owyhee (Murphy)

1P Payette (Payette)

2P Power (American Falls)

S Shoshone (Wallace)

1T Teton (Driggs)

2T Twin Falls (Twin Falls)

V Valley (Cascade)

W Washington (Weiser)


This format allows law enforcement officers and other officials to quickly identify where a vehicle is registered, which can be useful in a variety of situations. For example, if a vehicle is reported stolen, law enforcement can use the license plate number to determine which county the vehicle is registered in and contact the appropriate authorities.


Idaho license plates have undergone several design changes over the years. The state's first license plates were issued in 1913 and featured a simple design with the words "Idaho" and "1913" on a white background. Over the years, the design has evolved to include different images and color schemes.