In the South-eastern states. I live in Florida, and I see them all the time. A baby, probably just a few weeks old, was about a mile away from a pond and walked into my dad's work's garage. He almost stepped on it, then he found a box and took the turtle home. We named him Snappy.
I know for a fact they are in florida I see them all the time in lakes and rivers
Pet shops sometimes =D jk in florida