I live in northern Ohio. What happens to frog in the winter months? Do they die off or do they hibernate? Thank you.

Generally speaking, most frogs do not die in the winter - even in cold climates.

Here is some reference info about frogs from learner.org:

Q. Where do frogs go in winter?
A. Different species have different stategies for surviving winter. Northern leopard frogs, for example, pass the winter at the bottom of deeper lakes, far beneath the ice. They settle quietly on the lake bottom in deep water. They stay concealed behind a log or other debris to escape predators. Other types of frogs may hibernate under leaf litter.

Q. How do frogs survive the winter in cold places?
A. The frogs hibernate in burrows or bury themselves in mud. Toads and frogs are cold-blooded and their body processes slow down as the outside temperature drops. This is why you sometimes find frogs sunning themselves in the spring. Their body temp needs to rise for them to move well. Frogs' bodies have some natural antifreeze chemicals built into them, but a few kinds of frogs who live in especially cold climates can even survive being frozen solid.