Chris Bobbitt wrote:
>
In attempting to date certain commercially produced artifacts, it would be
very helpful to know when the two-capital-letter state abbreviations came
into use -- Ind. became IN, etc.   Also, does anyone have a handle on the
Calif. -> Cal.  and Penna. -> Penn. -> Pa. shifts in common usage?
   People in the post office here have no idea, and Polk's city directories
still use "Mich." on their title page!
   TIA,   Chris Bobbitt     [log in to unmask]
          Curator of Collections
          Monroe Co. Historical Museum
          Bloomington, Ind. (sic)
<
Quoting from Words into Type (third edition by Marjorie Skillin and Robert
Gay, Prentice-Hall, 1974):
"The following are the official abbreviations of the Post Office Department
for states, territories, and possessions of the United States. *** The
two-letter form following each abbreviation is the ZIP (Zone Improvement
Program) code. (The abbreviations in parentheses are not sanctioned by the
postal authorities but are used by many printers and in legal citations.)
 [There follows the list as promised, for which I give you a couple of
examples.]
Ind., IN
Pa. (Penn., Penna.), PA"
 
The Post Office Department first tried to regularize the many commonly used
abbreviations by fiat. I can't say with any certainty, but I think that
happened about sixty or seventy years ago. Then, with the introduction of the
ZIP code and the advent of optical character recognition, they took their
regularization even further: that would have been the late 1960s. So,
historically, it has been "Penna." then "Pa." then "PA". I recall having read
something put out by the United States Postal Service that explained why they
ordained this shift; if you're interested, try them in Washington DC.
 
This may have sped up the mail but it has proven vexatious when I have had to
copy-edit museum monographs -- everybody has their own inflexible idea of
what the "right" abbreviation should be. The solution that I worked out has
been to use the ZIP form in tight matter, like tabular work and catalogues
raisonnes, and to spell the states out completely in text -- and not to let
anyone else see it until it's printed.
 
Hope that's enough to solve the mystery.
 
Robert Biddle
San Marcos, California
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