Northwest of Santa Fe and west of Los Alamos, the 89,000 acre Valles Caldera National Preserve consists of high grassland valleys above 8,000 feet that hosting the largest elk herd in the southwest. This is an old volcanic caldera, reminiscent of Yellowstone National Park, surrounded by 11,000 foot peaks. The preserve is relatively untracked but does have several dirt roads and a few singletracks open to mountain biking.
To reach the preserve from Albequerque, head north on US25. Follow SR44 northwest through San Ysidro. Turn north on SR4 for 30 miles to the preserve gate.
Overall, Valles Caldera National Preserve is the 51st most popular mountain bike trail of all 53 mountain biking rides in New Mexico.