Thousand Island Lake Hike Mammoth, California

Thousand Island Lake Hike: Mammoth, California

California is known for incredible national parks and world-class backcountry hiking. For nearly one hundred years, wanderers have been venturing off into the great Sierra range looking for solitude while enjoying views of alpine lakes, jagged peaks, and the occasional brown bear.

Each summer, thousands set off to hike 500 or more miles on the Pacific Crest Trail, one of the longest thru-hikes in the world. The PCT covers 2,650 miles (4,260 km) from Mexico up to Canada, passing through California, Oregon, and Washington.

One little section of the PCT cuts through an area with breathtaking mountains, glacier-filled lakes, and raging rivers – it’s my absolute favorite weekend getaway in the Golden State. This area is called the Ansel Adams Wilderness. 

Various trails allow for day hikes or multi-day hikes for several days in this area. In our opinion, the best hike is out to Thousand Island Lake. This moderate to difficult hike has jagged minarets and beautiful panoramas. What we loved about this hike was the combination of the distance, elevation, views, lakes, mountains, and just enough tranquility and solitude to make this one of the best hikes in California.

Next time you strap on those hiking boots, we suggest you go on the Thousand Island Lakes hike in the Ansel Adams Wilderness.

Content and photographs provided by Yana Kogan and Timon.

Thousand Island Lake Hike: Mammoth, California

Best Time to Hike in Ansel Adams Wilderness

Thousand Island Lake: Loop High Trail
View from the High Trail

The best time to visit is during the summer and fall. Due to the high elevation, snow can potentially cover the area through May.

Keep in mind, in June there are millions of mosquitoes that make dusk and dawn a pretty horrible time to be outside. Either avoid this time to hike, or bring mosquito masks to cover your face and make sure to have long sleeves and long pants.

How to Get to Ansel Adams Wilderness

Thousand Island Hike: Lake
Stream leading up to Thousand Island Lake

The heart of the Ansel Adams Wilderness and hiking the Thousand Island Lake hike is in Mammoth Lakes, California. On the eastern side of the Sierras, this mountain town has a winter ski village that turns into an adventure sports center in the summer with world-class downhill bike courses.

All of the hikes are close to the Mammoth Lake visitor center. To get to the trailhead for the Thousand Island Lake hike, you must take a shuttle bus from the visitor center to the Agnew Meadows trailhead or the Devil’s Postpile depending on your start location. 

Parking is available at Mammoth Lakes near the ski lifts.

Hiking Permits

Thousand Island Lake: Trail Garnet Lake
Garnet Lake

This is a loop hike that requires a permit. You can reserve permits in advance or by walk-in at the Mammoth Lakes Welcome Center. It is located at 2510 Main Street, Route 203.

Different routes for the area have quotas on the number of hikers allowed each day. Arrive early in the morning for your best chance to get a permit. Reservations can also be made in advance for Inyo National Forest Trailheads at

Hike Details: Thousand Island Lake Loop

Thousand Island Lake: Backpacking Ediza Lake
Ediza Lake

Trailhead Start & Finish: Agnew Meadows
Distance: 27 miles (44 km)
Elevation Gain: 4,500+ feet (1,370+ meters)
Time: 3 days
Difficulty: Difficult

Day 1: Agnew Meadows to Thousand Island Lake via PCT

Thousand Island Lake: Loop Ediza Lake
Ediza Lake

Distance: 9 miles (14.5 km)

Begin the hike from Agnew Meadows at the High Trail trailhead, which is also the Pacific Crest Trail. From the back of the small parking area, the trail immediately begins with switchbacks ascending up to the top of the ridge.

This entire hike is exposed. Several miles of the hike follows the ridgeline with views of the Minarets and Shadow Lake. There are minimal water sources until Thousand Island Lake, so be sure you’re prepared.

Once you reach the river, you are close to Thousand Island Lake. Pick a nice camp spot along the river or continue a little further to camp next to the lake.

Day 2: Thousand Island Lake to Iceberg Lake via JMT and Shadow Creek Trail

Thousand Island Hike: Iceberg Lake
Iceberg Lake

Distance: 8 Miles (12.9 km)

After a morning stroll around Thousand Island Lake, take the JMT to Garnett Lake. It’s the largest lake in the area and a great place to relax, or if you’re brave enough, go for a swim. There is a trail that encircles the lake if you are up for a detour. We had a nice break to enjoy the views of the snow-capped Minarets behind the lake.

Continue on the JMT at the westernmost point of the lake. There is a stream flowing out of the river at this point, requiring you to walk over the bridge. Turn right to continue on the JMT. 

Following the 10,000-foot pass in this section, the trail descends down into the forest. The trail will intersect with another trail, leading you to Shadow Lake (left) or Ediza Lake (right). Turn right and continue on the trail along the eastern shores of Ediza Lake.

Look for the small sign for Iceberg Lake. The trail has a short but steep incline until reaching a flat plateau area with several streams. When you reach Iceberg Lake, you will realize why this is our favorite hike in California. Find some dry flat ground and camp the night.

Day 3: Ediza Lake to Agnew Meadows via Shadow Creek Trail and JMT

Thousand Island Lake: Trail Minarets

Distance: 7 Miles (11.3 km)

Return to Ediza Lake and continue on the trail you came in on towards Shadow Lake. Follow the Shadow Creek Trail along the lake. The trail then connects to the River Trail. Turn right to return to Agnew Meadows. This last day will be a total descent of nearly 2,000 feet.

Wait for the shuttle, and make a quick stop at the Devil’s Postpile National Monument, before heading back to Mammoth Lakes parking area.

What to Bring on the Hike

Thousand Island Lake: Backpacking Devil's Postpile
Devil’s Postpile
  • Tent
  • Sleeping bag
  • Sleeping pads
  • Water filter
  • Sunblock
  • Cooking stove & fuel
  • Cookware
  • Bathing suit
  • Small utility rope to hang clothes
  • Hiking shoes
  • Headlamps
  • Light waterproof jacket
  • Pack rain cover
  • Lighter
  • Bug repellent

Hiking Tips

  • Rent bear-proof canisters from the visitors center, which are required on this hike.
  • During the months of June and July, this hike is overrun with mosquitos. Make sure to bring proper repellent, long sleeve shirts for sunrise/sunset, and bring Benadryl for excessive bites.

That’s It – we hope you have a wonderful time exploring Thousand Island Lake!

Planning a trip to California? Check out our favorite books and travel guides!



  • Yana and Timon

    Yana & Timon met at college in Boston, Massachusetts. After graduating, they started their professional careers. They moved to San Francisco in 2010, a city they loved living in for nearly six years.

    After working and saving up money for several years, they quit their jobs and set off on an adventure of a lifetime. They started living a nomadic lifestyle in December 2015 and have not looked back since.

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1 thought on “Thousand Island Lake Hike: Mammoth, California”

  1. When did you hike this? I am planning for memorial weekend even if there is some snow fields to trek through.

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