When I was a kid, the nuns taught us to abbreviate California as Calif. We learned this in the early grades, when we learned how to write letters. I was an adult before I saw CA being used commonly, and now the old way looks strange. Did anyone else learn it that way?
I did !
I am also old enough to remember #### and Jane [Di-ck and Jane] "See spot run."
Calif. bought the plates and the rights to #### and Jane and every kid in the public school system in California learned to read from those books for decades.
Until the publishing industry fronted a couple teachers to sue Calif. over the right to make the school districts spend millions and millions on a teacher's right to make students read what she wants them too.
Edit- I guess Mathew hates the shorthand for Richard ?

Overview
At the playground, at the pet store, on a car trip, or at home: Dick, Jane, and Sally always have fun. Will Dick get another dog? Will Sally finally win a game of hide-and-go-seek? And who are Dick and Jane's favorite friends? With short stories and text from the original Dick and Jane basic readers, this is a perfect chapter book for eager new readers!

The books are now available as a reprinted series,
a series of 27, and there was a salacious Columbia movie named "Fun with Di-ck and Jane," (no hyphen in Di-ck) with Jane Fonda. That seems to be the thing that killed the use of the books in classrooms.
Calif. was the way we wrote "California" in grade school, too.
Then in about 1968 it was shortened to "Cal."
But perhaps
not to be confused with Cal Worthington and his dog Spot, (Spot was the name of Di-ck and Jane's dog, too, by the way!), they went to "Ca." for a short time before the two-letter abbreviations for the states came into vogue, "CA."
I think the biggest hurdle for that was all the "M" states
Michigan
Minnesota
Mississippi
Maryland
Massachusetts
Maine
Montana
Missouri
FOUR of which begin with "Mi..."
Missouri seems to have been at the bottom of the list, because someone else somehow got "MI" and "MS," leaving them with "MO." That usually means
"modus operandi," but it's not as bad as "MU" which is very tiny in scientific notation (x10^-9), or "MR" which means mentally retarded. But maybe Missouri didn't want MS anyway (due to multiple sclerosis).
.