Fort Huachuca is an active Army installation near Sierra Vista that functions like a small city all its own, but with higher security. As the headquarters of the U.S. Army Intelligence Center and many other military operations, you probably wouldn't think of it as a place to go mountain biking. Like any other city in the San Pedro Valley, however, access to the outdoors is phenomenal. Fort Huachuca sits right at the base of the mountains, encompasses a lot of terrain on this northeast flank of the range, and has trails to go with it.
Though not exactly public land in the sense that a national forest is, these trails are open to the public, as is most of the rest of Fort Huachuca. Guests need simply request access at the Van Deman Gate in Sierra Vista. This is a bit of a process that requires waiting in line, filling out a form, and undergoing a background check. It all goes fairly quickly if they are not busy, and the wait could be worth it if you want scenic riding in a very novel location.
Once you have your access badge, proceed along Hatfield Street then Smith Avenue, which turns into Canelo Road, following signs for Wren Arena. This is the fort's rodeo arena, but on most days it sits empty. Park behind the arena and get ready to ride. There are no defined routes here, but there are plenty of paths to follow. Most of the canyons and ridgelines have jeep roads ascending them, and some singletrack weaves in between. It is essentially a spiderweb of trails with infinite combinations. Locals have a few circuits with names like "Red Loop" and "High School Loop," but they are not marked and the variations are many. It's best to set off with a taste for exploration and choose your own adventure.
You will find trails of various character and difficulty. In general, trails that stay at the base of the hills are easy, those that ascend the canyons are intermediate, and those on the ridgelines are hard. Many of the trails are sandy or gravelly, especially on the ridges, making traction extra difficult. Steep and exciting sections are easy to find and also easy to avoid. Take your time to find a suitable route and enjoy the natural scenery as well as the military flair.
From ridges you will see mountains and valleys stretching away along with signal towers and an aerial radar blimp. In the canyons you may spot wildlife and concrete bunkers used to store explosives. The strange juxtaposition of scenery and the unusual privilege of being able to witness it makes the trip to Fort Huachuca worthwhile on its own, and the riding is fun to boot.