I think you mean Billings, MT (Montana), not Billings, MO (Missouri).
Geez! You're getting all my mistakes lately!
I think I knew that somewhere, but I didn't feel like typing the whole state name, and stopped there.
...and yes, there is a Billings in Missouri. It's a little SW of Springfield, MO, in the SW corner of the state. If you DO plan on going there for shopping, you'll be within easy commuting distance of Zen's place.
Oh good grief,.. there IS a springfield in every state, isn't there?
The two-letter abbreviations are frequently the first two letters, but not always, as evidenced in this example. If you really care, you can see all the official two-letter abbrevations for US states & territories at the US Postal Service site here or even on the Canada Post site here.
You know, I used to know a lot of them,... I used to "Wander" the states via things like Streets and trips, and google Earth. (You should see my bookmarks in GE!) YOu see the names and abbreviations there sometimes.