The Great Miami River, a tributary of the Ohio River, begins north of Dayton and flows through Cincinnati. Great Miami channel cats average 18 to 24 inches, with some fish up to 32 inches. There are some flatheads, especially closer to the Ohio River. The flatheads tend to be near the 24-inch mark, with some fish topping 36 inches. Most experienced anglers fish the rivers deep holes and washouts. Best tactics are casting live or dead bait upstream and letting the bait drift through the hole. Water depths on the Great Miami River can vary depending on where you are fishing. The important thing is to find sudden depth changes. There are multiple access sites on the river between Dayton and Cincinnati. According to Trueb, wildlife officers surveyed the river and marked these locations on a topographic map.