It’s a popular Southern expression, although I suspect it’s nearly universal. But we need to make sure ending sentences with at is a custom we stop practicing.
I’ve heard it my entire life. I don’t remember for sure, but there’s a reasonable chance that when I was a baby in my crib and I overheard someone construct a sentence like, “Where’s his toy at?” I probably started crying. When I was a baby, of course, I wouldn’t have been able to point out the grammatical error that had just been committed, but I at least knew it sounded like a horrible mistake.
“Where is he at?”
“Where is she at?”
“Where are they at?”
Behind the at.
Yes, it’s an old grammar joke. But it’s true. So why is ending sentences with at such a problem? For two reasons: the first is that it is generally improper to end sentences with prepositions. This rule is a little fluid, however, in conversational English. There’s that famous quote attributed to Winston Churchill, a man known for his beautiful use of the English language, who was criticized for ending a sentence with a preposition. Angry with his detractor, Churchill supposedly said, “This is something up with which I shall not put.”
I don’t know that it’s true, but it sounds like something Churchill might have said.
Ending a sentence with a preposition, while generally frowned upon in writing class, may be a better choice than an otherwise awkwardly arranged sentence that would result from not ending a sentence with a preposition.
The bigger reason ending a sentence with at is a problem is that it’s redundant: Where means “at what location”. So asking, “Where is it?” means “At what location is it?” You wouldn’t ask it that way, of course, but you certainly wouldn’t ask, “At what location is it at?” unless you were seriously trying for a smack upside the head. (And you’d deserve one, too.)
As lazy as the general public seems to be when it comes to using our language correctly, I’ve always found a little amusement in the sentence, “Where is he at?” (Amusement that follows the initial cringe, I might add.) Saying, “Where is he at?” means you’ve put in 25% more effort than necessary. You’ve wasted energy for no good reason.
And you still deserve that smack upside the head.