The Mad River is a river located in the west central part of the U.S. state of Ohio. It flows nearly 60 mi (97 km) from Logan County, to downtown Dayton, where it meets the Great Miami River. The river flows southwest from its source near Campbell Hill through West Liberty, along U.S. Route 68 west of Urbana, past Springfield (where it meets up with Buck Creek), then along State Route 4 into Dayton. It makes its confluence with the Great Miami River at Deeds Park. The first road between Cincinnati and Dayton that opened up the "Mad River Country" to European settlement was the Mad River Road, cut in 1797.

According to Dennis Bitton "Too many people talk about how smart a brown trout is. These fish have a brain smaller than a pea, like any other trout. They've been hunted with hook and line longer than any North American trout, and the instincts they've developed may make them harder to catch (sometimes) than other trout, but please don't call them 'smart'. Don't let them become aware of your presence, match what they are eating, when they are eating, and you'll discover the mythical 'wary old brown trout' can be caught by mortal man".