Again, Tom, George and Jim answer this question.

“Beginning in 1957, most types of North American plates were the standard size of 6 by 12 inches. Prior to that, varied sizes and shapes were common. Plates were normally rectangular, but oval, square, round, and triangular shapes were commonly used. For a number of years, Kansas and Tennessee die cut their plates to match the shape of the state itself.”  Next week we’ll talk about unusually shaped plates through the years.  In the meantime, if you have a comment or question, I’d love to hear from you….