Red Mountain is a volcanic cinder cone located in the Coconino National Forest of northern Arizona, United States, 25 miles northwest of Flagstaff. It rises 1,000 feet above the surroundings terrain and is shaped like the letter "U", with its opening towards the west. Geological Survey and Northern Arizona University scientists suggest that Red Mountain wa…Red Mountain is a volcanic cinder cone located in the Coconino National Forest of northern Arizona, United States, 25 miles northwest of Flagstaff. It rises 1,000 feet above the surroundings terrain and is shaped like the letter "U", with its opening towards the west. Geological Survey and Northern Arizona University scientists suggest that Red Mountain was formed in eruptions nearly 740,000 years ago.