Darton Dome
Darton Dome is an 8,413-foot (2,564-meter) volcanic summit north of Flagstaff, Arizona, immediately east of O’Leary Peak and northwest of Sunset Crater Volcano National Monument. It belongs to the San Francisco Volcanic Field, the vast volcanic landscape that surrounds the much higher San Francisco Peaks.
Although Darton Dome receives far less attention than neighboring O’Leary Peak or Sunset Crater, it is an interesting mountain in its own right. The forested dome is an older volcanic feature composed largely of dacitic rock, and hikers traveling the O’Leary Peak road pass close to its western slopes.
⚡ Fast Facts
| Feature | Details |
|---|---|
| Country | United States |
| State | Arizona |
| County | Coconino County |
| Region | San Francisco Volcanic Field |
| Elevation | 8,413 ft / 2,564 m |
| Prominence | 365 ft / 111 m |
| Isolation | 0.51 mi / 0.82 km |
| Nearest Higher Neighbor (NHN) | O’Leary Peak |
| Mountain Type | Lava dome |
| Rock Type | Primarily dacite |
| Alternate Name | Turkey Ridge |
| Land Management | Coconino National Forest |
| Coordinates | 35.3942° N, 111.5196° W |
Recent LiDAR-based peak data places Darton Dome at approximately 8,412.5 feet, with about 364.7 feet of prominence. Its nearest higher terrain is O’Leary Peak, less than a mile away.
🌋 A Lava Dome in Northern Arizona
Darton Dome is part of the enormous San Francisco Volcanic Field, which contains hundreds of volcanic vents spread across northern Arizona.
Unlike the classic cone-shaped form of nearby Sunset Crater, Darton Dome is a lava dome. Lava domes develop when magma is so viscous that it cannot flow far from its vent. Instead, the thick lava accumulates around the eruption point, gradually building a rounded or steep-sided volcanic mass.
National Park Service geological material identifies both Darton Dome and neighboring O’Leary Peak as lava domes and dates their volcanic activity to roughly 250,000 to 170,000 years ago.
That makes Darton Dome dramatically older than Sunset Crater, which erupted only about a thousand years ago.
🪨 The Geology of Darton Dome
Darton Dome is closely associated with the volcanic complex surrounding O’Leary Peak.
Geological research into the O’Leary volcanic suite has identified a mixture of rhyolite, rhyodacite, dacite, and andesite in the complex. Darton Dome itself is associated particularly with dacitic magma, while other portions of the O’Leary complex contain rhyodacite domes and flows.
Dacite is a silica-rich volcanic rock. Magma of this composition tends to be relatively viscous, helping explain why the landscape developed rounded lava domes rather than long, fluid lava flows.
The O’Leary–Darton volcanic complex therefore provides a striking contrast with the younger basaltic cinder cones and lava flows scattered across much of the surrounding San Francisco Volcanic Field.
🌋 Darton Dome and Sunset Crater
Darton Dome is particularly easy to appreciate from the area around Sunset Crater Volcano National Monument.
From the Bonito Lava Flow and surrounding viewpoints, O’Leary Peak and Darton Dome rise together beyond the dark volcanic landscape. O’Leary forms the larger mountain to the west, while Darton Dome appears as the rounded summit to its east.
This view brings several different generations of volcanic activity into a single panorama.
The foreground contains the rugged basalt of the relatively recent Bonito Lava Flow. Behind it rise the much older Darton Dome and O’Leary volcanic complex. Farther west, the massive San Francisco Peaks represent another chapter in the region’s long volcanic history.
The National Park Service describes O’Leary Mountain and Darton Dome as among the oldest and most massive volcanic features immediately northwest of Sunset Crater National Monument.
🏔️ Relationship With O’Leary Peak
Darton Dome sits immediately east of O’Leary Peak, and the two mountains dominate the skyline north of Sunset Crater.
O’Leary is considerably higher and more prominent, reaching nearly 8,950 feet and supporting a fire lookout. Darton Dome rises only about half a mile from higher terrain associated with O’Leary, giving it relatively modest isolation.
The two peaks are separated by a saddle crossed by the road leading toward O’Leary Lookout.
Arizona Highways describes this saddle at roughly 8,000 feet and notes that hikers following the O’Leary Peak route pass directly between O’Leary Peak and Darton Dome.
That makes Darton one of the easiest additional summits for experienced peakbaggers to combine with an O’Leary Peak outing.
🥾 Hiking Darton Dome
There is no maintained trail to the summit of Darton Dome.
The most practical access is generally from the road used for the O’Leary Peak hike. This old Forest Service road begins near O’Leary Group Campground and climbs gradually before entering a series of switchbacks toward the saddle between the two peaks.
From the road, Darton Dome requires a short off-trail climb.
One documented peakbagging route leaves the O’Leary road for a brief ascent directly toward Darton’s summit. The climb is comparatively short, although there is no established trail and the wooded summit limits the views.
Hikers attempting the dome should be comfortable navigating away from maintained trails and should avoid creating new paths where possible.
🌲 A Forested Summit
Unlike Sunset Crater’s stark cinder-covered slopes, Darton Dome is heavily forested.
Ponderosa pine dominates much of the surrounding landscape, with other high-country vegetation appearing according to elevation, slope, and moisture. The tree cover continues nearly to the summit and is dense enough that Darton is not primarily a panoramic viewpoint.
That distinguishes it from neighboring O’Leary Peak, where the lookout area provides expansive vistas.
Darton’s appeal is instead its quiet setting, volcanic geology, and the opportunity to reach a relatively obscure Arizona summit only a short distance from a well-traveled hiking route.
🌄 Views Around Darton Dome
Although vegetation obscures many views from the summit itself, the surrounding slopes and nearby O’Leary road offer much broader perspectives.
To the west rise O’Leary Peak and the distant San Francisco Peaks. The skyline of the main massif includes Humphreys Peak, Agassiz Peak, Doyle Peak, Rees Peak, and Sugarloaf Peak.
To the south and southeast, younger volcanic terrain surrounds Sunset Crater and the Bonito Lava Flow.
The contrast between these features helps illustrate the remarkable variety of volcanic landforms concentrated around Flagstaff.
🏷️ The Turkey Ridge Name
Darton Dome has also historically been known as Turkey Ridge.
The U.S. Geological Survey’s Arizona geographic-name records list Turkey Ridge as a variant name for Darton Dome and record the official Darton Dome name as a recognized summit in Coconino County. The same records give its traditional mapped elevation as 8,408 feet.
Modern LiDAR measurements have refined the elevation slightly upward to approximately 8,413 feet.
🗺️ Darton Dome on USGS Maps
Darton Dome appears on the USGS O’Leary Peak 7.5-minute quadrangle, along with O’Leary Peak, Sunset Crater, the Bonito Lava Flow, Robinson Mountain, and portions of San Francisco Mountain.
The official mapping places Darton east of O’Leary Peak and immediately north of the volcanic terrain protected within Sunset Crater Volcano National Monument.
For hikers considering an off-trail summit attempt, a detailed topographic map is particularly useful because Darton lacks a maintained summit trail.
☀️ Best Time to Visit
Late spring through autumn generally provides the easiest conditions for exploring Darton Dome.
Summer temperatures are mild compared with Arizona’s low deserts, although thunderstorms frequently develop over northern Arizona during the monsoon season. Early starts are advisable when storms are forecast.
Autumn brings cooler temperatures and patches of changing aspen around the higher terrain near O’Leary Peak and the San Francisco Peaks.
Winter can bring significant snow and ice. Because reaching Darton involves off-trail travel, snow can make the otherwise short summit excursion substantially more challenging.
Visitors should also check current Coconino National Forest closures and fire restrictions before beginning a trip.
🌎 The San Francisco Volcanic Field
Darton Dome belongs to one of the most remarkable volcanic regions in the United States.
The San Francisco Volcanic Field extends across a large portion of northern Arizona and contains hundreds of volcanic vents representing several million years of activity.
These volcanoes take many forms, including cinder cones, lava flows, lava domes, and large composite volcanoes.
The San Francisco Peaks represent the remains of the field’s enormous San Francisco Mountain stratovolcano. Elden Mountain is another prominent lava-dome complex near Flagstaff, while Sunset Crater represents one of the field’s youngest eruptions.
Darton Dome falls between these extremes: an older Pleistocene lava dome preserved beside a landscape transformed by much younger volcanic activity.
📸 What Makes Darton Dome Special?
Darton Dome is unlikely to compete with Humphreys Peak or Sunset Crater for fame, but it adds another fascinating piece to northern Arizona’s volcanic puzzle.
Its modest prominence, wooded summit, and lack of a maintained trail make it a destination primarily for peakbaggers and hikers interested in exploring beyond the better-known attractions around Flagstaff.
Geologically, however, Darton Dome is especially worthwhile. Standing beside O’Leary Peak and overlooking the much younger landscape around Sunset Crater, it helps reveal just how long volcanism has shaped this part of Arizona.
For anyone exploring the lesser-known summits of the San Francisco Volcanic Field, Darton Dome is a small mountain with a surprisingly large geological story.
🔗 Related Articles
- O’Leary Peak
- Sunset Crater
- San Francisco Peaks
- Sugarloaf Peak
- Rees Peak
- Doyle Peak
- Humphreys Peak
- Elden Mountain
📚 Sources
- Peakbagger — Arizona Peak Data
- U.S. Geological Survey — O’Leary Peak Quadrangle
- U.S. Geological Survey — National Gazetteer of Arizona
- National Park Service — Roadside Geology of Sunset Crater Volcano National Monument
- National Park Service — Sunset Crater Volcano National Monument Environmental Assessment
- Arizona Highways — O’Leary Peak Trail
- University of Michigan — Magma Mixing in the San Francisco Volcanic Field
