Vehicle registration plates of Oklahoma

The U.S. state of Oklahoma first required its residents to register their motor vehicles and display license plates in 1915.

In 1956, the U.S. states and Canadian provinces came to an agreement with the Automobile Manufacturers Association that fixed the size for license plates for vehicles, except those for motorcycles, at six inches in height by twelve inches in width, with standardized mounting holes. The 1955 (dated 1956) issue was the first Oklahoma license plate that complied with these standards.

The order of the numeric county codes used from 1952-61 was based on the populations of each county according to the 1950 United States Census, and the order of the codes used in 1962 was based on the populations of each county according to the 1960 Census.

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