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13,689 ft · San Juan Mountains, Colorado

Mount Oso

Mount Oso is a 13,689 ft peak in the San Juan Mountains, Colorado. The standard route is the Mt. Oso SE Ridge: 25 mi, 7,100 ft of gain, Class 2.

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Mount Oso in the San Juan Mountains, Colorado

Mount Oso at a glance

  • Elevation13,689 ft4,172 m
  • RouteMt. Oso SE RidgeClass 2
  • Distance25 mi7,100 ft gain
  • Time16 – 18 hrsVery Hard effort
  • SeasonJul – Sep
  • RangeSan Juan MountainsColorado

Climbing the Mt. Oso SE Ridge

Mount Oso sits in the San Juan Mountains. The usual ascent is Mt. Oso SE Ridge, rated Class 2. Plan about 25.3 miles round-trip with roughly 7,100 ft of gain from about 11,800 ft. Expect a rough 4WD approach road. Summer monsoon storms build fast, so start early and be off the summit by early afternoon. Watch for loose rock, route-finding on talus, and brief exposed steps where the terrain steepens. Stats and approach details follow climb13ers.com. Bring layers for cold wind on the summit ridge.

Gear and hazards

What to bring

  • Backpack (55–75 L)
  • Hiking Boots
  • Water
  • Offline Maps
  • Headlamp
  • Satellite Communicator
  • Whistle
  • Sunglasses
  • Sunscreen
  • Sun Hat
  • Midlayer
  • Insulated Jacket
  • Hardshell Jacket
  • Warm Hat
  • Buff
  • Midweight Gloves
  • Trekking Poles
  • GPS Device
  • Power Bank
  • Water Filter
  • First-Aid Kit
  • Emergency Bivy

What to watch for

  • Storms
  • High altitude
  • Route-finding difficulty

Quests with Mount Oso

Peaks near Mount Oso

  1. Irving Peak

    Irving Peak

    13,216 ft · 1.2 mi away

  2. Weminuche Peak

    Weminuche Peak

    13,240 ft · 1.9 mi away

  3. UN 13,350 (near Irving Peak)

    UN 13,350 (near Irving Peak)

    13,350 ft · 2.1 mi away

  4. UN 13164

    UN 13164

    13,164 ft · 3.9 mi away

Frequently asked questions

How tall is Mount Oso?

Mount Oso is 13,689 feet (4,172 m) tall. It is in the San Juan Mountains, Colorado. It is also known as Oso, Mt.

How does Mount Oso rank among the Colorado 13ers?

At 13,689 feet, Mount Oso is the 101st highest of the 582 Colorado 13ers. The highest is Grizzly Peak.

How hard is it to hike Mount Oso?

The Mt. Oso SE Ridge is Class 2, which means off-trail hiking with some use of your hands for balance. Yak rates the overall effort very hard: 25 miles with 7,100 feet of elevation gain.

How long does it take to hike Mount Oso?

Most people take 16 – 18 hours round trip on the Mt. Oso SE Ridge, covering 25 miles with 7,100 feet of elevation gain. That is a long day, so start before dawn and set a turnaround time.

Can a beginner hike Mount Oso?

The Mt. Oso SE Ridge needs no climbing skills, but it is a very hard day: 25 miles with 7,100 feet of elevation gain. Build up on shorter hikes first, start early and carry plenty of water and layers.

Will you get altitude sickness on Mount Oso?

You might. Most people feel the altitude above 8,000 feet, and Mount Oso reaches 13,689 feet. Spend a night or two at elevation first, drink plenty of water and turn back if a headache, nausea or dizziness gets worse.

What time should you start hiking Mount Oso?

Early. Afternoon thunderstorms are common in summer, so aim to be off the summit and the exposed upper mountain by early afternoon. At 16 – 18 hours round trip, many parties start in the dark.

When is the best time to hike Mount Oso?

The usual hiking window is July to September. Outside it, expect snow, storms or closed access, and check the summit forecast before you go.

Climb Mount Oso with Yak

Plan your route on a topo map, check the summit forecast, then log your climb and see what is left on your list

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