Clarence Cannon Dam and Mark Twain Lake is at 20642 SR J. The 285-mile shoreline of this 18,600-acre site provides 12 recreation areas with facilities for a variety of activities, including boating, fishing, swimming, camping, hiking and hunting. Summer campfire programs about the natural and cultural history of the area are presented at three amphitheaters.
The M.W. Boudreaux Memorial Visitor Center, at the south end of the dam, houses exhibits about the dam's construction as well as displays about area history, environmental awareness and hydroelectricity. Interactive exhibits demonstrate power generation by letting visitors crank turbines by hand to power light bulbs. The Northeast Missouri Vietnam Memorial is at the southeast corner of the building; its plaques list the names of 45 men from the area who died serving in Vietnam.