I have heard of townlet, not sure where but it popped in my head.
When the pilgrims came over they created a settlement.
John Mellencamp wrote about small-town USA.
And in the Midwest I have heard small towns referred to as outposts.
A remote part of a country or empire.
I will add that there are a lot of slang phrases too. There was an old phrase, a one-horse town, that was used well when people rode horses.
Now I hear, a one stop-sign town or one gas-station town. Or varieties off of this.
People may also say they live in the middle-of-nowhere or the boonies ,boondocks, or the sticks. There are a lot of terms for unincorporated America.
You can also use the word bum-fuck instead of your town name.
.. "Where do you live?"
"I live in bum-fuck Ohio."
"Where's it at?"
"Little town near Perryville out in the middle of no where. We got a stop sign on D7."
Edit: Another term popped in my head that I still hear a lot - East Jesus. Someone would say, "Damn you live all the way out in East Jesus." Meaning a very small town out in the middle of no where.