Mount Lemmon

Arizona Class 1 Santa Catalina Mountains

Rank 54

Elevation landscape

9,171 ft

Prominence height

5,164 ft

Difficulty signal_cellular_alt

Class 1

Est. Time schedule

4–6 hr

Distance route

4–9 mi

Vert Gain trending_up

2,000–3,500 ft

Mount Lemmon ranks No. 55 among the 57 ultra-prominent peaks in the contiguous United States, rising 9,171 feet in the Santa Catalina Mountains north of Tucson, Arizona, with 5,164 feet of clean prominence. It is the highest summit in the Santa Catalina Mountains and Pima County. Most hikers use the Aspen Trail and Marshall Gulch Trail from Marshall Gulch for roughly 4 to 9 miles round-trip with about 2,000 to 3,500 feet of gain on Class 1 terrain. A Coronado National Forest or Interagency pass is required to park at Marshall Gulch.

The peak carries the O'odham name Babad Do'ag, meaning Frog Mountain, and was later named for botanist Sara Plummer Lemmon, who reached the summit on her 1881 honeymoon. The Catalina Highway climbs roughly 27 miles from the desert edge to the summit zone, gaining more than 6,500 feet in the process, an elevation change that compresses the ecological equivalent of driving from Mexico to Canada into a single mountain corridor.

The summit area supports mixed conifer and fir forest entirely unlike the surrounding Sonoran Desert. This abrupt transition, combined with 5,164 feet of prominence, makes the peak a significant ecological island above the desert floor. The summit zone includes the Lemmon Rock Lookout fire tower and the village of Summerhaven. Mount Lemmon Ski Valley, on the north face near the summit, is widely noted as the southernmost ski area in the continental United States.

Recommended Route

Aspen Trail / Marshall Gulch Trail

The primary foot approaches to the summit use the Aspen Trail and the Marshall Gulch Trail, both of which begin at Marshall Gulch Picnic Area at the end of the road south of Summerhaven. The two trails are commonly combined as a loop of approximately 3.9 miles with around 1,500 feet of gain. Parties seeking the true summit can continue from Marshall Saddle via the Aspen Trail's upper section toward the summit zone, adding mileage and gain; because roads reach the upper mountain, total hiking distance and elevation gain vary considerably depending on chosen trailhead and finishing point. The terrain is maintained trail throughout, remaining Class 1 with no scrambling required. The Lemmon Rock Lookout Trail provides an alternate approach from a different point along the Catalina Highway.

Key Landmarks

Marshall Gulch Picnic Area (standard trailhead south of Summerhaven)
Marshall Saddle (junction for summit extension via upper Aspen Trail)
Lemmon Rock Lookout Trail (alternate Catalina Highway approach)

warning

The summit is often 20 to 30 degrees Fahrenheit cooler than Tucson, especially during warm-season afternoons. Summer thunderstorms build rapidly on the ridgeline from July through September; plan to be off exposed terrain before midday.

Permits & Camping

Climbing Permits

No hiking permit or trail quota applies on Mount Lemmon or in the surrounding Santa Catalinas within Coronado National Forest. Parking at Marshall Gulch Picnic Area requires a Coronado National Forest or Interagency pass; day-use passes are available on-site for $8 per vehicle. Marshall Gulch is a day-use area; overnight parking for backpackers is permitted at the trailhead only, and picnicking overnight is not permitted. Confirm current fee rules and any seasonal gate closures with the Santa Catalina Ranger District before your trip.

Camping & Wilderness

Dispersed camping is available on Coronado National Forest land in the Santa Catalinas at no charge, subject to current fire restrictions and camping regulations. The upper Catalina Highway gate is closed seasonally from December 15 through February 28, restricting vehicle access to the Marshall Gulch area during that period. Fire restrictions are common and can be strict in this region; check current conditions with the Santa Catalina Ranger District before any overnight trip.

Summit N 32.44330° W 110.78820°. Marshall Gulch Picnic Area: N 32.42806° W 110.75528°. Elevation 9,171 ft; prominence 5,164 ft. Coronado National Forest, Santa Catalina Mountains.

Wildlife & Seasonal Conditions

Mount Lemmon is Class 1 on maintained trails for all standard foot routes. No technical gear or scrambling skills are required under normal conditions. The primary hazards are weather: summer thunderstorms can develop quickly above the ridgeline between July and September, and winter can bring snow, ice, road closures, and hazardous footing at upper elevations. Wind exposure near the summit is significant year-round. The mountain's southerly latitude means winter snow melts faster than on ranges farther north, but upper trails can remain icy or snow-covered from late fall through early spring.