An International Dark Sky City, Flagstaff sits next to Mount Elden, Humphreys Peak and south of the San Francisco Peaks on the southwestern edge of the Colorado Plateau. Around 7,000 feet in elevation, it is along the western side of the largest contiguous ponderosa pine forest in the United States. A stop along Historic Route 66, it is reachable along I-17, I-40, Routes 93, 89 and 89A. It also houses Northern Arizona University, U.S. Naval Observatory and the U.S. Geological Survey.