Most people have never heard of the Pinaleño Mountains. That's part of what makes them extraordinary.

The actual name "Pinaleño" comes from an Indian word meaning "many deer" — or "deer mountain." It's an appropriate name. The Pinaleños are capped by 10,720-foot Mount Graham, the tallest of southeastern Arizona's sky island mountain ranges. The Pinaleño Mountains are the single most diverse mountain range in North America and host 11 endemic species found nowhere else on Earth. Driving up here is the ecological equivalent of traveling from Mexico to Canada in a single afternoon.

The Swift Trail — The Drive Is the Destination

State Route 366, also known as the Swift Trail Parkway, offers access to this beautiful mountain range, climbing more than 7,000 feet over 35 miles with incredible views of the surrounding landscape. The first 22 miles are paved; the last 13 miles are dirt and require a high-clearance vehicle. Visitors pass through eight distinct life zones in just a dozen miles — Sonoran desert, Sonoran grassland, chaparral, pinyon-juniper woodland, Madrean evergreen oak woodland, ponderosa pine forest, mixed conifer forest, and subalpine forest.

Pull over at every overlook you can. The road is narrow with steep dropoffs and no guardrails on much of the upper section — drive with patience and watch for oncoming traffic on blind curves.

Along the way, watch for the plaque marking Jacobson Canyon — one of the named drainages carved into the slopes of Mount Graham along AZ-366. The canyon holds the remains of an old mill, a quiet remnant of the logging and settlement era that shaped this mountain in the late 1800s. Easy to drive past, worth stopping for.

Near the upper elevations, keep an eye out for the Ice Caves. Near Soldier Creek, huge house-sized rocks have tumbled together to form caves between them — some so deep that ice can be found in their depths even in July and August.

Campgrounds Along the Swift Trail

Mount Graham has one of the most complete campground lineups of any Arizona mountain range, spread across the full elevation range of the Swift Trail. Campgrounds include Arcadia, Columbine Corrals, Cunningham, Hospital Flat, Noon Creek, Riggs Flat, Shannon, Soldier Creek, and Stockton Pass. Group sites include Riggs Flat, Stockton Pass, Treasure Park East and North, Twilight, Upper Arcadia, and Upper Hospital Flat. All individual sites run approximately $20/night. Reservations via Recreation.gov where available.

Arcadia Campground is the first campground visitors encounter heading up the Swift Trail, shaded by tall ponderosa pine interspersed with Gambel oaks and Arizona walnuts — excellent for birding. The Arcadia Trail #328 starts here and leads up the mountain to Shannon Campground, with a 1-mile spur to the top of Heliograph Peak — a designated National Recreation Trail.

Treasure Park East and North sit in a mountain meadow at 9,000 feet and each accommodate up to 100 people. Legend has it that stolen gold and silver was buried here by outlaws in the 1850s, marked with a triangle of three colored granite stones — though no treasure was ever found.

Dispersed Camping is available at several areas including Clark Peak Corrals, Cluff Dairy, Frye Mesa Reservoir Lakes, and Grant Creek. Clark Peak Corrals sits near 9,000 feet in mixed-conifer forest at the end of NFS Road 803 — the last dispersed camping area on the upper mountain. Standard 14-day stay limit applies.

Upper Hospital Flat — Base Camp

We camped two nights at the Upper Hospital Flat Group Site — a meadow-edged clearing along Big Creek in mixed conifer forest at around 9,000 feet. In the 1880s, the campground served as the site for a field hospital for ailing soldiers from nearby Fort Grant. The restorative powers of this cool, high-elevation location also attracted officers and their families seeking a summer refuge from desert heat. That same cool air is what draws campers today.

The campsite delivered from the moment we arrived. Coues white-tailed deer moved in and out of camp freely — close enough to study, calm enough to make you feel like the guest. Chipmunks worked the perimeter. The late summer meadow was flush with wildflowers and wild mushrooms of every size. At night a mouse found its way into our trash can — we freed it and sent it on its way. The forest here is big, old, and quiet in a way that takes a few hours to settle into.

After dark, a neighbor appeared across the hill and began hauling equipment up and down the slope — lights, cases, unusual gear. A small mystery that kept us watching. The next day we found out he was an entomologist, up in the dark collecting and studying insects at elevation. The Pinaleños attract that kind of dedicated scientific attention — and for good reason.

The Mount Graham Red Squirrel

The campsite sits near the refugium for one of Arizona's rarest animals. The Mount Graham red squirrel is an endangered subspecies of the southwestern red squirrel, native only to the Pinaleño Mountains of Arizona. The subspecies was believed to be extinct in the 1950s, but was rediscovered in the 1970s and listed as endangered in 1987. In 1988, the U.S. Fish and Wildlife Service designated most of the highest elevations as a red squirrel refugium, with access restricted by a permit system administered by the USDA Forest Service.

We saw them. Small, quick, rust-colored — darting through the conifers with the confidence of an animal that owns the place. Seeing an endangered species in its only habitat on earth is not something you forget.

Good news as of late 2024: the annual interagency population survey estimated 233 squirrels — a significant increase from 144 estimated in 2023. The mountain is slowly winning.

Into the Forest

We hiked into the forest and found the closed road leading toward the refugium — a reminder that some places are protected for a reason and that boundary deserves respect. Along the higher trail, wild raspberries grew along the path — ripe, sweet, and completely unexpected at that elevation.

At one point I heard an odd sound in the forest — something in distress, possibly a young deer. I stopped and recorded it for a while but never did determine what it was. The Pinaleños have that effect. There's always something moving just out of sight.

Notable Landmarks

Columbine Visitor Center sits along the Swift Trail and is open weekends during summer. Indoor and outdoor exhibits cover the mountain's natural and cultural history — worth a stop on the way up or down.

Heliograph Peak is one of the highest points in southeastern Arizona, accessible via a 1-mile spur off Arcadia Trail. Named for the heliograph signal station operated here by the U.S. Army in the 1880s during the Apache campaigns.

Mount Graham International Observatory is situated near the summit and hosts some of the world's most powerful telescopes including the Large Binocular Telescope. Tours are available on select days — check the observatory website before visiting. Note: the observatory has been controversial, built on land sacred to the Western Apache and in habitat critical to the red squirrel.

Riggs Flat Lake

Riggs Flat Lake is a small picturesque lake, 11 acres in size, set in alpine forest and meadow. Its cold waters are stocked during the summer with rainbow, brown and brook trout. Small boats are permitted on the lake, but most people fish from the shoreline. West Peak is visible from the vicinity of the lake, as are Aravaipa Valley and the Galiuro Mountains to the west from a short hike to an overlook.

We walked the full shoreline. Signage at the lake noted an active bald eagle nest in the area, and others had spotted it that morning — but we didn't catch sight of it ourselves. Large lizards moved along the rocky edges. Squirrels worked the tree line. The lake sits at the end of the Swift Trail and feels like a reward for the drive — quiet, cold, and completely removed from the desert world below.

The View on the Way Out

On the drive down we stopped at a pullout with an open view across the valley. Far below, Fort Grant was visible — the same fort whose soldiers once climbed this mountain seeking relief from the heat. Fort Grant was closed in 1905 and now serves as an Arizona State Prison Facility. The view connects nearly 150 years of history in a single glance.

More Information

• Upper road (Swift Trail) closed November 15 – April 15 — plan your trip accordingly; lower campgrounds remain accessible year-round

• High-clearance vehicle recommended for last 13 miles of dirt road to Riggs Flat Lake

• Vehicles and trailers over 22 feet combined length not recommended — switchbacks on AZ-366 are tight

• Day use fee at Riggs Flat Lake: $8/day

• Camping at Riggs Flat Campground: ~$20/night

• Red squirrel refugium is closed to the public without a permit — stay on designated trails and respect all closure signs

• Nearest hospital: Mt. Graham Community Hospital, Safford