Oklahoma has four mountain ranges. The Ozarks (sometimes referred to as a plateau) in northeast Oklahoma rise from the plains to a height of more than 2,000 feet. The Ouachita Mountains (including the neighboring Kiamichi Mountains) are pine-covered peaks located in southeast Oklahoma. While most mountain ranges run north-south, the ridge lines of the Ouachita’s run east-west. The Ouachitas, which have a rougher topography than any other region in the state, are the highest mountain range between the Rocky Mountains and the Appalachian Mountains. In southwest Oklahoma, the Wichita Mountains, now ranging from 600 to 2,475 feet and covered with granite boulders, were once as high as the Rocky Mountains. The ancient Arbuckle Mountains of south central Oklahoma are composed of limestone, shale, granite and sandstone.