On occasion, New Mexicans will refer to our state as “NM”.
More frequently, though, it is “No, you idiot! I said* NEW* Mexico! I’m a U.S. citizen, just like you, you moron!”
The state university is called N.M.S.U., frequently pronounced “enema-zoo” when you are mad at the administration.
I know I’ve never lived there, but when did this change occur, eh? Did the citizens of DC decide that Washington sucked and gave the city the boot. Do you address your mail:
4 Main Street
DC
Are you jealous of the state of Washington and upset that the city has to share a name? I know in slang and common speech, it’s referred to simply as DC, but the name of the city is Washington, located in the District of Columbia, rather than a state. It’s kind of like Berlin - it’s a city, but it’s also its own state, though in Washington’s case, it’s a federal district rather than a state.
California is a “Republic” nowhere except on its flag. The four “Commonwealths” are commonwealths in name only. Under the constitution, they are all states. The word “commonwealth” has no specific meaning under the constitution.
I wish it were that simple, but I have to say Washington State or people here (New England) will assume I mean DC.
I definitely say “Penna” and “Mass” but when I lived in NYC I would say The Bronx, Manhattan, etc., not usually New York or New York City.
And “St. Louis, MO” flies.
As someone who lives near DC, I can assure you that “Washington”, without qualifiers or some other established context, will be instantly taken to mean the capital city — because that’s its name. You need to say “Washington state” to refer to the state, if the referent isn’t otherwise obvious. I think that’s not only true around here, but for just about all of the U.S. east of the Mississippi.
Whether this is fair or sensible I cannot say, but it’s still the convention around these parts. Sorry if it bugs you.
Not in Ohio. Here, people are just as likely to mean the state as the city, and often prefer to refer to the city as DC.
All right, let me retreat a little and say, “most of the east coast” instead.
I’ll admit though that I don’t have any kind of survey to back that up. I’m just going by the experience of my own personal travels.
Yes, and that used to be the postal abbreviation for MA, or at least the way most people wrote it. I still have to force myself to write MA and CT instead of Mass. and Conn. Kids these days just have no respect for tradition. 
I don’t generally call the state itself Mass, though, unless it’s associated with something else-- the Mass Pike, Boston Mass, Mass Ave, etc…
1980s pro wrestling tag team and proported rock band The Freebirds had a line in their entrance music that went something like:
Bad Street, Atlanta G-A
Baddest street in the whole U.S.A.
I don’t think I’ve ever heard Georgia referred to as “G A” outside of that song, though.
Texas is simply referred to as texas. Our initals are two consonants anyways, its easier to just say the name alltogether.
They call her Hard Hearted Hannah
The vamp of Savannah
The vamp of Savannah G. A.
–“Hard Hearted Hannah”, hit song by Yellen & Ager, 1924
Mmm-hmm. I didn’t even know the province I lived in was named anything other than just “BC” until I was 8 or so. That’s all anyone ever calls it.
And at the other coast, the Province of Prince Edward Island is often referred to as “PEI.”
Residents of Northern Virginia do not call Northern Virginia NoVa, we call Northern Virginia Community College NoVa/NOVA.
Besides DC, I’m curious whether other territories go by their initials.
It wouldn’t surprise me if PR, VI, AS, or CZ were used. That last, not so much anymore.
There are also FM, GU, MH, PW, and someone please tell me how we got MP. 
Yep, Missouri gets chopped down to “Moe” a lot. Example:
Person A- “You work in KC?” (Kansas City)
Person B- “Yeah KC MO, not KCK.” (Kansas City, Kansas)
FYI, it’s irritating when people not from this region assume Kansas City is in Kansas. Especially to folks on the Missouri side. Though I understand the assumption (OKC and others).
In conversation, I always refer to Washington D.C. simply as “D.C.”