Our largest turtle is the Snapping Turtle, Chelydra serpentina, shown above. Adults regularly grow to lengths of two feet or more, and they’re happy to spend sunny weather lording over Geauga County ponds!
Though they’re the largest, they’re not the candidates for the turtle you saw. Beartown Lakes also hosts the much-smaller Painted Turtle and Eastern Musk Turtle (both of which are smaller than a dinner plate).
Other locations in Geauga County have also turned up the odd Northern Map Turtle and the occasional Northern Spiny Softshell Turtle. (The Northern Spiny Softshell Turtle is smaller than a typical Snapping Turtle, but it does have a distinctly long neck. As far as I know, the only Geauga County location where a Softshell Turtle has been reported is the LaDue Reservoir.)
Have a look at the terrific “Reptiles Of Ohio Field Guide” from the Ohio Division of Wildlife, and see if you can spot your turtle.
-Naturalist Chris Mentrek