Mount Hopkins, 8,580', Santa Rita Mountains

Essence: Begin in Madera Canyon and ascend on a series of established trails, a social trail, and the Mount Hopkins Road to the summit. There are excellent views from the road as it spirals to the apex with a 1,480-foot prominence. The high point was graded flat in the 1970s to accommodate the MMT Observatory. I put off climbing Mount Hopkins for many years, unclear about permissible access by the hiking public and the viability of the informal trail up the east ridge. The "Mt. Hopkins Trail" is better than advertised. There were no signs prohibiting travel by the public and I sensed we were welcome. However, permission for walking up the road might be fluid, check. The peak is named for Gilbert W. Hopkins, a mining engineer with the Santa Rita Mining Company and member of Arizona's first Territorial Legislature. He was killed by Apaches in the shadow of the mountain in 1865. The hike is within the Mount Wrightson Wilderness managed by Coronado National Forest. 

Travel: There are three Green Valley exits from I-19. Watch for a brown sign for Madera Canyon Recreation Area and exit on Continental Road. Turn east under the interstate and cross the Santa Cruz River. In 1.2 miles, turn south on White House Canyon Road which transitions to Madera Canyon Road. Cross three one-lane bridges. The paved road steepens and ends at 12.8 miles in a multi-layered parking lot at the Madera Canyon Picnic Area. Loop around and park near the Old Baldy Trailhead located in the upper lot on the east side. Pay the day use fee or display your National Interagency Pass.
Distance and Elevation Gain: 8.6 miles; 3,200 feet
Total Time: 4:30 to 6:00
Difficulty: Trail, social trail, paved road; navigation moderate; Class 2 with no exposure
Map: Mount Hopkins, AZ 7.5' USGS Quad
Date Hiked: February 4, 2025

Fred Lawrence Whipple Observatory: The complex has a suite of telescopes designed for a wide variety of purposes at varying elevations on the mountain. The summit observatory is operated jointly by the Smithsonian Astrophysical Observatory and the University of Arizona for solar system, galactic and extragalactic astronomy. The Visitor & Science Center at the base of the mountain houses a Gamma Ray Detector.
Quote: The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff. We are a way for the universe to know itself. Carl Sagan

 

Seen from the crown of Devils Throne, Mount Hopkins is a study in contrasts. Composed of granite and clad in a climax forest, the western slopes flow out and downward, grounding the mountain on the desert floor. And from its upper reaches, astronomers probe the mysteries of the universe in wonderment. (Thomas Holt Ward, photo)

Route: Walk south on the Old Baldy Trail for 0.3 mile and transition onto the Vault Mine Trail. In 0.7 mile, continue south on the Carrie Nation Trail to the Agua Caliente Trail. Hike west for a short distance and cut south to the east ridge of Hopkins. Ascend on the Mt. Hopkins Trail to the Mount Hopkins Road. Spiral up to the summit.

Both the Vault Mine and Carrie Nation trails are depicted on the signboard at the trailhead, elevation 5,440 feet. The route utilizes four established trails and climbs 1,900 feet over 2.2 miles to the east ridge of Mount Hopkins. Begin by hiking south on the Old Baldy Trail.

Southern Arizona was suffering through a years-long drought in 2025. The south tributary of Madera Canyon was stone dry and we saw no wildflowers blooming on the entire hike. We were delighted by the quirky-jointed white trunks of the sycamore. Deciduous and conifer trees include silverleaf and Arizona white oak, alligator juniper, madrone, and Arizona walnut. The diversity of pines is staggering--Southwestern white pine, longleaf pine, Chihuahua pine, ponderosa pine, and Apache pine. (THW, photo)

At 0.3 mile the Old Baldy Trail breaks to the left and heads toward Mount Wrightson. Continue straight, following the sign for Agua Caliente Saddle. This is the beginning of the Vault Mine Trail, the Very Steep Trail.

 

Enter the Mount Wrightson Wilderness. The silence and solitude inherent in the protected landscape contributes to making Madera Canyon a world renown destination for the birding community. 

 

The trail pitches up stone risers made of boulders and bedrock.

Reach the junction of the Vault Mine and Carrie Nation trails at 0.7 mile, 5,900 feet. The trail sign isn't terribly helpful. This juncture is the beginning of the Carrie Nation Trail which ascends south (straight ahead) and ends at the Agua Caliente Trail. This description uses the Carrie Nation because it is the shortest path to the Mount Hopkins summit. However, if you wish to extend your tour, the Vault Mine Trail will enrich your day. It climbs southwest up the wall of Madera Canyon on a lateral ridge, pitching up 1,400 feet in one mile. I recommend descending on it to take advantage of the stellar views of the Santa Rita Crest through periodic openings.

 

Walk in or alongside the canyon floor, a rocky proposition either way.

At 0.9 mile, 6,000 feet, the Carrie Nation makes a significant switchback to bypass a restriction in the creek. The canyon rises to meet the trail once again 360 vertical feet later. At 1.5 miles, arrive at a spring and the Carrie Nation Mine. Discarded mining equipment includes a boiler stamped "Indianapolis, IND, Henry B Front," a crankshaft for a steam engine, piston, and drive wheel.

 

An adit was bored deep into the earth, disappearing into the darkness. Exploring underground mines is not recommended by this blog! The trail crosses to the east side of the creek.

The End Of Trail sign marks the end of the maintained trail. It is another half mile to the Agua Caliente Trail and the Carrie Nation "Extension Trail" gets right after it. The thin footpath doesn't see a lot of use but it is plenty clear all the way to the top. The trail punches up an interior ridge basically at the angle of the spine itself with some short switchbacks thrown in to ameliorate the pitch. Chipped rock and rubble clutter the trail surface. If that wasn't wild enough, we saw bear scat, cougar scat, and a white-tailed deer and yearlings. (THW, photo)

Arrive at the unsigned junction with the Agua Caliente Trail at 2.0 miles, elevation 7,240 feet. If you intend to return on the Carrie Nation make a mental note of this location. The Agua Caliente Trail is an east-west lateral that holds the 7,200-foot contour from Josephine Saddle to Agua Caliente Saddle where it dives west into its namesake canyon. Turn west and hike just 0.15 mile, watching for an unmarked trail going a few steps up to the divide and base of Hopkin's east ridge. 

Your landscape marker for the start of the Mt. Hopkins Trail is the "Witness Tree," a venerable and ancient alligator juniper. Easily 800 years old, we always plan to take a break in its presence, pausing to commune in word and touch. Trees talk low and slow. Initiate the conversation and then get real quiet and listen. (THW, photo)

It is a mere half mile up the east ridge to the Mount Hopkins Road. Figure about half an hour. Look for the start of the trail just left of the Witness Tree. (THW, photo)

We'd heard stories of hikers getting lost on the unmaintained trail but we had no difficulty following it. You do need to pay close attention to stay on track. The trail is absolutely necessary for barging through vegetation. There was no sign of recent use on the thin path. But traffic is frequent enough to keep the trail alive. It starts out on the ridgeline.

 

There were no braids to begin. The footpath moves off the ridge on the north for a time. We built a couple rows of rocks blocking loose ends that confused us (and others) momentarily. Our track is spot on. The trail ends at the microwave transceiver, image-center-right. The summit telescope is center-left. (THW, photo)

 

The top of the trail is not cairned so note its location as it pops out onto the road.  

The trail ends on a service road to the installation shown at 2.7 miles, 7,860 feet. Turn left to contact the Mount Hopkins Road, 1.6 miles from the summit. We had hoped to avoid the road altogether by going straight up the east ridge, shown. It looked plausible on the map. The brush was so annoying we quickly gave up, disappointed. It would have been extraordinary to experience the natural mountain.

This image looks onto Mount Hopkins Road from our short east ridge attempt. (THW, photo)

 

The stroll up the road turned out to be incredibly pleasant as we spiraled up to the summit. We had the road completely to ourselves. Not one vehicle passed us. The road is cleaved into the side of the mountain laying bare its composition. The rock is a coarse-grained, intrusive crystalline granite. If it looks familiar, that's because it's the same stone that Elephant Head is made of.

The views are superb from every angle. Look east to the peaks on the Santa Rita Crest, Mount Wrightson (almost 900 feet taller than Hopkins), and Josephine Peak. The trail made contact with the road at the hairpin.

Look south over mid-mountain installations to range after range fading out into the blue distance in Mexico.

As the road wrapped to the west we looked way down on the start of the observatory road cutting between Devils Throne and Peak 5,012. Devils Cash Box is the rightmost peak on the ridgeline. The Visitor & Science Center can be seen on the west side of the Three Devils. The Metric Highway follows the course of the Santa Cruz River and the Tumacacori Mountains frame the valley on the west. Walking north, Elephant Head's granitescape is a sharpened blade. (THW, photo)

The summit observatory was built on top of a massive block of granite--the perfect foundation for a rotating building.

In days gone by astronomers came to the mountain to look directly through telescopes. There is a neglected picnic area nestled in the trees and dormitories. Now star gazing is done remotely with digital sensors. The road pitches up as it makes the final twist onto the summit.

Arrive on the summit at 4.3 miles. The crest of the mountain was leveled off to accommodate the largest visible-light telescope at the Fred Lawrence Whipple Observatory. Known as the MMT Observatory (Multiple Mirror Telescope), the original design built in 1979 consisted of six mirrors working in consort. Those mirrors were replaced in 2000 with a mirror 21 feet in diameter, cast and polished by the University of Arizona in Tucson. The telescope is owned by the Smithsonian Astrophysical Observatory and jointly operated with the university. The building rotates to see the entire starfield. The yellow sign reads: "Caution: Stand clear of rotating building. Audible alarm when rotating." The ground surface is crushed white rock and a fence wraps the periphery. (THW, photo)  

A placard placed by the Smithsonian Institution labels the mountains in the west. In this image Baboquivari Peak is appropriately in the center. 

Here's the diagram closeup.

 

From the summit, look down on Pete Mountain and the ever magnetic Elephant Head. 

We wanted to descend on the north ridge. We had a track from a gnarly person who pulled it off. The ridge is not at all obvious and we couldn't get a bead on it despite poking all over. I got snarled in a massive tangle of New Mexico locust, the ultimate bushwhacking hazard. It did not align with our philosophy that exploring mountains should ideally be fun. So we extracted ourselves and headed back down the road after a pleasant lunch in the abandoned picnic area.

 

When you arrive back on the Agua Caliente Trail there are choices. The shortest way back to the trailhead is on the Carrie Nation Trail. Or, you may walk west on the Agua Caliente to the Vault Mine Trail. If you head east, the Agua Caliente flanks Jack Mountain (an easy climb for the best view of Wrightson possible) and ends at Josephine Saddle. You no doubt know how to get home from there.