[ProtectOurFreedom]

Didn’t PA exist long before zip codes? I know Penn and Penna were common, but I vaguely recall PA, too. It’s probably bad memory.

[Publius]

Pa. did in fact exist, but when the two letter codes came in, it became PA

[LouieFisk]

“Didn’t PA exist long before zip codes?”
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Yup, as I wrote, “PA” was even used in a 1950s Chuck Berry song’s lyric.