Bunsen Peak Trail

Four people hike across a talus slope with the sun setting behind a mountain in the distance.

Bunsen Peak is a 4.6-mile day hike with a serious 1,300-foot elevation gain in Yellowstone's northern section. The trail climbs through forest and meadow via relentless switchbacks to an alpine summit offering panoramic views of Swan Lake Flats, the Gallatin Mountains, Blacktail Deer Plateau, and the Yellowstone River Valley. Grizzly bears frequent this area—noise discipline is mandatory. This is a moderately strenuous ascent; expect 3-4 hours round-trip if you're fit.

Quick facts

Distance Miles: 4.6
Route Type: Out-and-back
Difficulty Level: Moderately strenuous—lung-buster
Elevation Gain Feet: 1300

Trail profile

Distance Miles: 4.6
Route Type: Out-and-back
Difficulty Level: Moderately strenuous—lung-buster
Elevation Gain Feet: 1300
Estimated Time: 2-3 hours official estimate; realistically 3-4 hours for most hikers, 4-5 if building fitness.
Trail Surface: Forest floor transitioning to loose scree and talus near summit
Trail Features: Swan Lake Flats views
Gallatin Mountain Range vistas
Alpine summit panorama
Blacktail Deer Plateau views
Yellowstone River Valley views
Northern park overview
Communications tower at summit
Trail Highlights: Panoramic summit views across northern Yellowstone. 360-degree vistas of Swan Lake Flats, Gallatin Mountains, Blacktail Deer Plateau, and Yellowstone River Valley. Alpine terrain with serious exposure.

Trailhead & access

Trailhead Location: 5 miles south of Mammoth on the Grand Loop Road. Park in the gravel lot just south of Golden Gate, across from the Glen Creek trailhead.
Parking Lot Size: Small unpaved gravel lot with limited capacity
Parking Fill Time: Full by 7:30-8:00 AM during peak season (summer)
Shuttle Required: 0
Shuttle Details: No shuttle system

Permits & conditions

Permit Details: No permits required
Fees: $35 park entrance (private vehicle). No additional trail-specific fee.
Trail Status: Open
Seasonal Closures: Road access limited outside mid-April through early November; full winter closure typical

Facilities & rules

Restrooms At Trailhead: 0
Water Sources: None on trail; carry all water required
Accessibility: Steep exposed switchbacks, scrambling near summit, loose terrain—not wheelchair or stroller accessible

Safety & strategy

Hazards: Grizzly bears
Steep exposure
Alpine weather
Loose scree and talus
Lightning risk at summit
Steep descent
Hazard Details: Grizzly bears frequent this area—mandatory noise discipline and bear spray. Steep exposure with unprotected terrain. Alpine weather develops fast; afternoon thunderstorms are common. Loose scree on descent is slippery when wet. Lightning risk at high elevation. Steep switchbacks on descent punish tired knees.
Cell Service: Spotty; rely on park ranger services
Crowd Level: Busy in summer; conga line in peak season mornings
Peak Crowd Times: 7:00 AM to 11:00 AM, June through August
Best Season: Summer and Fall
Best Time To Visit: Start by 6:00 AM in summer or early fall. Mid-September through early October offers the most stable weather and fewer crowds. Arrive at the gravel trailhead by 7:30 AM—the lot fills fast during peak season.
Tips Advice: Tighten your boots hard—2.3 miles of switchbacks will punish loose lacing
Carry minimum 2-3 liters of water; no sources on trail, high elevation increases thirst
Make constant noise (talk, clap); grizzly territory demands audible presence
Trekking poles are mandatory for the 1,300-foot descent; saves your knees and adds stability
Start by 6:00 AM; afternoon thunderstorms develop fast at elevation
Check road status before driving—Grand Loop Road segments close outside mid-April to early November
The summit has an active communications tower; stay clear and stay focused on descent

More details

Park Area: Mammoth Hot Springs
Trail Markers: Well worn and marked
Dogs Allowed: No
Biking Allowed: No; hiking only
Shade Level: Mixed. Forest provides shade for the first 1.5 miles; final 1 mile is full sun alpine terrain.
Emergency Contacts: Nearest ranger station: Mammoth District Ranger Station (5 miles north)
Map Recommended: 1
Snow Dates: Snow typically blocks trail October through May
Mud Season: April and May muddy; post-rain conditions slick
Fall Colors Peak: Late September through early October
Bug Season: June and July peak mosquito season
Insider Tips: The false summit at treeline will trick you—the real summit is another 0.3 miles through alpine scrub
Bring bear spray and know how to use it; this is legitimate grizzly habitat
The gravel parking lot is genuinely small; arrive early or accept being turned away
Summer afternoon thunderstorms develop fast at this elevation; summit and descend before 2:00 PM
The ridge descent is steep and loose in places; don't rush
Family Friendly Notes: Not recommended for young children. The 1,300-foot elevation gain is serious; switchbacks are relentless. Grizzly bear presence requires constant supervision and noise discipline. Only suitable for fit children (10+) with hiking experience and adult supervision.
Nearby Facilities: Mammoth Campground (5 miles north), Mammoth Visitor Center, lodging and dining at Mammoth area
Review Summary: Hikers praise the summit views and north park panorama, but warn that the elevation gain is brutally steep and the descent is harder than expected. Grizzly bear precautions are essential. Popular and crowded in summer.

Frequently asked questions

Are there bears on this trail?

Yes, grizzlies frequent this area. Carry bear spray, make constant noise (talk, clap, sing), and hike with a partner if possible. Bear bells are insufficient.

Is this trail safe to do alone?

Not ideal. You're climbing into grizzly country with significant exposure at altitude. Partners provide both safety and communication redundancy. At minimum, file a trip plan.

Do I need special gear?

Trekking poles are strongly recommended, not optional. The descent is steep and loose. Bear spray is essential. Sturdy boots required—no trail runners. Bring a headlamp; start before 6 AM.

What fitness level is required?

You need to be comfortable with sustained uphill over 2+ miles. If you can't do 30 minutes of stairs without stopping, this will hurt. It's not technical, but it's a serious grind.

Will I have enough water?

No sources on the trail. Carry 2-3 liters minimum depending on temperature. High elevation plus exposure equals increased thirst. A typical hiker drinks 1L per hour on this climb.

Is it worth the effort?

Yes, if you want genuine panoramic summit views of northern Yellowstone. The views justify the pain. But you're climbing for views, not a leisurely forest walk.

How crowded will it be?

Busy in summer, especially 7-11 AM. Arriving by 6:30 AM helps. Early fall (late September through October) is quieter. Come expecting company in peak season.