It could either be a three toed box turtle, or a tan phase Gulf Coast Box turtle. From the picture, it looks like a Three Toed Box Turtle, but if it has four toes on its rear feet, I would say gulf coast. Unless its a mix.

If you could take a picture of its rear feet, and the bottom part of its shell, it may be helpful.

It has a terrible over-bite, that needs to be corrected - either by a vet, or feeding him on a rock, this will help wear down its beak. Cuttle fish bones may help as well.

Other than that, looks healthy.

Bill