Sounds like it could be and hatchling stinkpot but I don't recall them having an orange belly. Could be a mud turtle too (Kinosternon sp.).
Anyway they both are hatched at just under an inch.
What state did you find it? That would help with the ID.
Releasing in the nearest body (relative to where it was found) of permanant water in some aqautic vegetation is the thing to do if you are not going to keep it. Anyway, there are many breeders who produce captive hatched ones if you really want one.
Still, a wild caught hatchling makes a great turtle if you are prepared to care for it properly.