Thousand Island Lakes 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 that are my absolute favorite weekend getaway in the Golden State. This area is called the Ansel Adams Wilderness. 


Several trails allow for day hikes or multi-day hikes for several days in this area. The best hike is to the Thousand Island Lakes. There are a few ways to create loop hikes with other stunning alpine lakes nearby. This moderate to difficult hike has jagged minarets and beautiful panoramas. What we loved about this hike was a 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.


Best Time to Hike in Ansel Adams Wilderness

The best time to go is during the Summer and Fall. Due to the high elevation snow can potentially be covering the area through May. Keep in mind, in June there are millions of mosquito’s which 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 sleeve clothing.


View from the High Trail


How to Get to Ansel Adams Wilderness

The heart of the Ansel Adams Wilderness and hiking the Thousand Island Lakes hike is Mammoth Lakes, California. On the eastern side of the Sierra’s, this mountain town has a winter ski village which turns into an adventure sports center in the summer with world-class downhill bike courses. All of the hikes are close to the Mammoth Lakes visitor center. To get to the trailhead for the Thousand Island Lakes 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.


Thousand Island Lakes Loop; Mammoth, California

Stream leading up to Thousand Island 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. 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

  • High Trail has a quota of 12 advanced and 8 walk-in permits

  • Shadow Creek Trail has a quota of 18 advanced and 12 walk-in permits

  • Thousand Island Lake Trail has a quota of 18 advanced and 12 walk-in permits

Thousand Island Lakes Loop; Mammoth, California

Garnet Lake

Hike Details: Thousand Island Lakes Loop

Trailhead Start & Finish: Agnew Meadows

Distance: 27 miles (44 km)

Elevation Gain: 4,500+ feet (1,370+ meters)

Time: 3 days

Difficulty: Difficult


Thousand Island Lakes Loop; Mammoth, California

Ediza Lake


Day 1: Agnew Meadows to Thousand Island Lake via PCT

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 are along the ridgeline with views of the Minarets and Shadow Lake. There are minimal water sources until Thousand Island Lakes. Once you reach the river, you are close to Thousand Island Lakes. Pick a nice camp spot along the river or continue a little further to camp next to the lake.


Thousand Island Lakes Loop; Mammoth, California

Ediza Lake

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

Distance: 8 Miles (12.9 km)

After a morning stroll around Thousand Island Lakes, take the JMT to Garnett Lake. It’s the largest lake in the area and a great place to relax, or if 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.


Thousand Island Lakes Loop; Mammoth, California

Iceberg Lake

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

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

  • 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


Devil’s Postpile


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.



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