The U.S. unincorporated territory of American Samoa first required its residents to register their motor vehicles and display license plates in 1924.
In 1956, the United States, Canada, and Mexico came to an agreement with the American Association of Motor Vehicle Administrators, the Automobile Manufacturers Association, and the National Safety Council that standardized the size for license plates for vehicles (except those for motorcycles) at in height by in width, with standardized mounting holes. American Samoa adopted these standards in 1977.