Monte Sano Nature Preserve is a protected area on Monte Sano Mountain in Huntsville, Alabama, spanning 1,107 acres and more than 23 miles of public trails managed by the Land Trust of North Alabama, many built by volunteers. Part of the final reach of the Appalachian chain, it preserves uncommon broadleaf hardwood habitat and plant species considered ecological relics that offer clues to ancient climates. Its trails support recreation and environmental education, and in 2011 they became the first in Madison County recognized as National Recreation Trails. The preserve also holds historically significant sites including Three Caves, Trough Springs, and remnants of the Monte Sano Railroad.