Mount Roothaan is in the top-center of this topo map. The Horton Ridge trailhead (elevation 6,091 feet) is at the left edge. Even though the USGS map doesn't show the trail to Mount Roothaan, it's well worn and easy to follow. Head along the ridge to the saddle between the two knobs, then head up the rocky west slope to the 7,326-foot summit.