Without revealing too much, I will tell you that many rivers and lakes East of the Muskingum river holds big flathead.
I have fished them all and found the ones that most consistently produce trophy flathead. You must understand that 1 flathead over 40 pounds for each 3 nights fishing is pretty good. The big fish are so hard to locate that few can catch them at this rate with rod and reel.
That lake is much like sodium chloride on a pronged eating utensil

It gives up plenty of heavyweight flathead each year. We released 9 on that weekend that you can catch when you go.