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13,575 ft · San Juan Mountains, Colorado

Greylock Mtn

Greylock Mtn is a 13,575 ft peak in the San Juan Mountains, Colorado. The standard route is the Sunlight Lake Access: 30 mi, 8,125 ft of gain, Class 2.

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Greylock Mtn in the San Juan Mountains, Colorado

Greylock Mtn at a glance

  • Elevation13,575 ft4,137 m
  • RouteSunlight Lake AccessClass 2
  • Distance30 mi8,125 ft gain
  • Time19 – 21 hrsVery Hard effort
  • SeasonJul – Sep
  • RangeSan Juan MountainsColorado

Climbing the Sunlight Lake Access

Greylock Mtn sits in the San Juan Mountains. The usual ascent is Sunlight Lake Access, rated Class 2. Plan about 30.2 miles round-trip with roughly 8,125 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 Greylock Mtn

Peaks near Greylock Mtn

  1. UN 13164

    UN 13164

    13,164 ft · 0.5 mi away

  2. Grizzly Peak

    Grizzly Peak

    13,700 ft · 1.0 mi away

  3. Windom Peak

    Windom Peak

    14,093 ft · 1.2 mi away

  4. Jupiter Mountain

    Jupiter Mountain

    13,838 ft · 1.3 mi away

Frequently asked questions

How tall is Greylock Mtn?

Greylock Mtn is 13,575 feet (4,137 m) tall. It is in the San Juan Mountains, Colorado.

How does Greylock Mtn rank among the Colorado 13ers?

At 13,575 feet, Greylock Mtn is the 152nd highest of the 582 Colorado 13ers. The highest is Grizzly Peak.

How hard is it to hike Greylock Mtn?

The Sunlight Lake Access is Class 2, which means off-trail hiking with some use of your hands for balance. Yak rates the overall effort very hard: 30 miles with 8,125 feet of elevation gain.

How long does it take to hike Greylock Mtn?

Most people take 19 – 21 hours round trip on the Sunlight Lake Access, covering 30 miles with 8,125 feet of elevation gain. That is a long day, so start before dawn and set a turnaround time.

Can a beginner hike Greylock Mtn?

The Sunlight Lake Access needs no climbing skills, but it is a very hard day: 30 miles with 8,125 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 Greylock Mtn?

You might. Most people feel the altitude above 8,000 feet, and Greylock Mtn reaches 13,575 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 Greylock Mtn?

Early. Afternoon thunderstorms are common in summer, so aim to be off the summit and the exposed upper mountain by early afternoon. At 19 – 21 hours round trip, many parties start in the dark.

When is the best time to hike Greylock Mtn?

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 Greylock Mtn 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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