The Flatside Wilderness is a 9,507-acre protected area in the U.S. state of Arkansas. It is one of six wilderness areas in the Ouachita National Forest and also the easternmost. Outdoor enthusiasts can enjoy the area in a number of ways, including an 8.9-mile section of the Ouachita National Recreation Trail.

The Ouachita Mountains, simply referred to as the Ouachitas, are a mountain range in western Arkansas and southeastern Oklahoma. They are formed by a thick succession of highly deformed Paleozoic strata constituting the Ouachita Fold and Thrust Belt, one of the important orogenic belts of North America. The Ouachitas continue in the subsurface to the northeast, where they make a poorly understood connection with the Appalachians and to the southwest, where they join with the Marathon uplift area of West Texas. Together with the Ozark Plateaus, the Ouachitas form the U.S. Interior Highlands. The highest natural point is Mount Magazine at 2,753 feet (839 m).