The Ouachita Mountains are a mountain range in west central Arkansas and southeastern Oklahoma. The range's subterranean roots may extend as far as central Texas, or beyond it to the current location of the Marathon Uplift. Along with the Ozark Mountains, the Ouachita Mountains form the U.S. Interior Highlands, one of the few major mountainous regions between the Rocky Mountains and the Appalachian Mountains.The highest peak in the Ouachitas is Mount Magazine in west-central Arkansas which rises to 2,753 feet (839 m).
The mountains are known to contain at least 15 endemic plant species (i.e. plants that occur nowhere else). These include Sabatia arkansana, Valerianella nuttallii, Liatris compacta and Quercus acerifolia.
The Ouachita Mountains contain the Ouachita National Forest
, Hot Springs National Park and Lake Ouachita, as well as numerous state parks and scenic byways. They also contain the Ouachita National Recreation Trail, a 223-mile-long (359 km) hiking trail through the heart of the mountains. The trail runs from Talimena State Park in Oklahoma to Pinnacle Mountain State Park near Little Rock, Arkansas. It is a well maintained, premier trail for hikers, backpackers, and mountain bikers (for only selected parts of the trail).
The Talimena Scenic Byway begins at Mena, Arkansas, and traverses 54 miles (87 km) of Winding Stair and Rich Mountains, long narrow east-west ridges which extend into Oklahoma. Rich Mountain reaches an elevation of 2,681 feet (817 m) in Arkansas near the Oklahoma border. The 2-lane winding road is similar in routing, construction, and scenery to the Blue Ridge Parkway of the Appalachian Mountains.