Backpacking Thousand Island Lake | Ansel Adams Wilderness

Backpacking Thousand Island Lake | Ansel Adams Wilderness

Backpacking Thousand Island Lake| Written by Brian Callender | Photography by Julie Boyd

Thousand Island Lake: Hike Details

Starting Elevation: 7,909 ft.

Distance: 21 miles (hiking as a loop)

Elevation Gain: 3,300

Hike Type: Overnight

Difficulty Level: Strenuous

Food Storage: There is 1, two-sided bear box located at each trailhead (High Trail/Shadow Lake Trail). It’s a bit surprising considering how popular the trails are here, so plan accordingly.

Restrooms: Two pit toilets at the start of the High Trail and two more can be found at the Shadow/River trailhead.

Cell Service: Limited service at the trailhead and then some service along the first portion of the High Trail. None at any of the lakes.

Crowd Factor: Very High. This is one of the most popular backpacking trails in the Mammoth area and we saw plenty of day-hikers and backpackers on our trip. Solitude is hard to come by in this area!

Parking: There is space for about 40 cars at the Shadow Lake/River Trail lot which is a lot less than you might think for a popular trailhead. Space for approximately 15-20 cars is available at the High Trail lot. Overflow parking options will all add to your mileage. Vehicles arriving after 7:00 a.m. during peak season will be required to take the shuttle.

Permit: Required for all overnight hikes and available through There are three main starting trailheads and each one is popular.

Date Hiked: 7/2-7/3, 2021

Chances are high that even if you have never been to Thousand Island Lake, you have seen a photo of it somewhere. With Banner Peak rising majestically over the dark blue water, it’s easily one of the most iconic and well-known lakes in the Eastern Sierra and perhaps all of California. Everyone from Pacific Crest Trail (PCT) and John Muir Trail (JMY) backpackers to day-hikers has this hike on their list and for good reason; it’s stunning. But seeing it in person makes it so much more special as it’s truly hard to do it proper justice in a photograph.

Getting to the Agnew Meadow Trailhead

From downtown Mammoth Lakes (As a beer lover, I use Mammoth Brewing Company as the starting point) it’s about a 20 minute drive to the trailhead at Agnew Meadows. Head south on Lake Mary Road, passing the Minaret Vista and Entrance Station and follow the signs. It’s important to note that  if you arrive after 7:00 a.m., you will be required to take a shuttle during the summer season. More information about the shuttle can be found on NPS website here. For this reason, and because parking spots are hard to come by, we highly recommend starting your day early.

Once you pass the Devil’s Postpipe National Monument entrance station, the road is mostly a single lane with some wider areas to pass. You’ll be going downhill here, so make sure you keep an eye on your speed. At the bottom of the hill, you will make a right and follow the signs for Agnew Meadow. Down the dirt road, there are two smallish parking lots, so find a spot wherever you can squeeze in. We arrived around 6:45 a.m. and luckily snagged one of the last spots.

Day 1: Agnew Meadows to Thousand Island Lake

There are three trails that start from Agnew Meadows that lead to Thousand Island Lake. Depending on which way you want to go, the options are: High, River, and Shadow Creek trails. On a previous hike in this area, we took the Shadow Creek Trail to Ediza Lake. Wanting to test a different route, we opted for the High Trail, heading towards Thousand Island Lake in a counterclockwise manner.

The High Trail (also known here as the PCT) starts off in the trees and quickly crosses a small creek via a short wooden footbridge. You’ll leave the shade of the trees behind just before reaching the half mile mark. From here, the trail gradually zig zags its way up as you make your way west.

After crossing the mile marker, the trail flattens out and dips back into the trees from time to time. You’ll catch sporadic glances of where you’re heading, but for the most part, the views are obscured by the trees. The trail is much of the same for the next couple of miles. It finally opens up to a pretty spectacular view of Shadow Lake and the Ritter Range. We soaked up the views and said goodbye to the shade once again as we left the trees behind.

What this next section of trail lacks in consistent shade (there are a few patches) it more than makes up for it in incredible scenery. Another bonus is the relative flatness here as you stroll along gazing across to the Ritter Range.

Just past the 4 mile mark, you’ll cross another small stream before the trail begins to climb again. At 4.35 miles, the trail begins a switchbacking descent. You’ll continue on this way for the next mile completely exposed to the sun. Just past the 5 mile mark, we decided to take a snack break under a well placed tree (you’ll know it when you see it!).

Thousand Island Lake

We finally reached the junction at 6.2 miles (the map said 5.1) which was fortunately in the shade. Stay to the left here to continue to Thousand Island Lake. Immediately after passing the junction, the trail begins to descend. It was somewhat bittersweet knowing we’ll have to climb again to reach Thousand Island Lake, but we always enjoy the easier sections and the break for our legs.

We reached another junction following a bit more climbing just past 7 miles. We took another break here, relishing the shade. Two small ponds appear at 7.5 miles and then another junction at 7.8 miles. After the latest junction, you’ll climb a bit before descending again and then connecting to the River Trail about 0.4 miles later.

The roaring sound of water flowing out of Thousand Island Lake lifted our spirits a bit as we knew were getting closer! At 8.7 miles, we finally caught our first clear glimpse of Banner Peak, which meant we were almost there. After what felt like a long final push, we reached the official shoreline of Thousand Island Lake at 9.25 miles and 2,200 feet of elevation gain.

Thousand Island Lake Thousand Island Lake

Wanting to get a less crowded campsite, we ended up hiking about another mile before finding a spot. Thousand Island Lake is massive, and you’ll notice when you arrive that many people choose to camp pretty early after arriving at the lake. Knowing that privacy is hard to come by with such a popular destination, we recommend continuing on as much as possible, to find a bit of solitude.

Thousand Island Lake

With it being late afternoon, we set up camp and took care of the usual chores. I wiped off the sunscreen and sweat and then took a quick dip in the lake to feel a bit cleaner and then Julie did the same. Following dinner Julie headed back out for some sunset photography while I relaxed in the tent.

Day 2: Thousand Island Lake to Garnet Lake

Thousand Island Lake

After packing up camp, we set off towards Garnet Lake. We retraced our steps along the shore of Thousand Island Lake, and then met up with the junction at the outlet to head towards Shadow Lake. You’ll quickly come to a crossing which is made easier by a wooden foot bridge. After the bridge, you’ll climb up about 100 feet where you’ll be greeted by Emerald Lake at 1.4 miles. In another 0.3 miles, you’ll arrive at the emerald waters of Ruby Lake. We enjoyed a short bit of downhill before the trail begins a steep, switchbacking grind up to a partial view of Garnet Lake.

Emerald Lake
Ruby Lake

The next section is a steep downhill heading towards Garnet Lake. We stayed to the left at the junction 2.75 miles (just over 13 total), but if you’re overnighting here you’ll want to make a slight right in order to reach camping spots.

Garnet Lake

Following a quick pit stop at the shore of Garnet Lake to have a snack and put our feet in the water, we were back on the trail. At the outlet of Garnet Lake, you’ll cross over another wooden footbridge and then approach a trail junction. The JMT continues south, which means heading slightly right.

In an effort to save some time and energy, we opted to head left on the unmaintained trail at the 14-mile mark. We followed the trail about a mile, hopping over some boulders at first and then taking a steep dirt section of switchbacks.

Eventually we reached the bottom of the trail, but in an effort to find an easier river crossing, went about a half mile out of our way. We ended up going back the way we came as there were no better spots to cross, and decided that we would just have to walk through the thigh-deep water as most of the rock crossings looked sketchy at best. If you plan on doing this section of trail, we highly recommend downloading a GPS map to use offline (we have AllTrails Pro) so you can check to make sure you are on the trail. There were definitely a few spots where we found it useful, and reassuring, to check to make sure we were headed the right way.

Back on the River Trail, we picked up our pace and daydreamed about the cold beers that were awaiting us in town.  The day was warm, and we were tired as we headed through the alternating sections of pine forest and exposed vistas of the river valley ahead of us. There were a few sections of uphill during this stretch, but this trail was mostly shaded and descending. However, when we hit the junction for the Shadow Lake Trail, we knew that those conditions would be changing soon.

Unfortunately, the last part of the trail ascends a few hundred more feet and is almost completely exposed to the sun the entire time. When we hiked to Ediza and Shadow Lakes previously, this was the most challenging section, and hiking out on this route again was no different. Tired, sore, and sweaty, we kept moving forward and made the final push out of the Ansel Adams Wilderness and back to the trailhead. A round of victory beers and burgers at the Mammoth Brewing Company never tasted so good, and it was the perfect way to celebrate finishing the hike we set out to complete last summer (we had to bail out due to the Creek Fire).

Final Thoughts on Backpacking Thousand Island Lake

Thousand Island Lake

A hike that had been on our bucket list for a few years, Thousand Island Lake definitely did not disappoint. This entire area and all of the lakes and peaks are picture perfect and well worth your time. We were so glad to have made it to Thousand Island and Garnet Lakes and hope to return again someday. If you’re looking for a single or multi-day backpacking trip into some of the most spectacular scenery the Eastern Sierra has to offer, we highly recommend a visit to Thousand Island Lake.


Backpacking the 20 Lakes Basin

Hiking the Little Lakes Valley

Backpacking Big Pine Lakes

Hiking Minaret Lake

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Thousand Island Lake

1 thought on “Backpacking Thousand Island Lake | Ansel Adams Wilderness”

  • Beautiful photos again! It looks like a hard climb with those rocks. The close up of the flower is beautiful too!

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