Near Agnew Meadows to Thousand Island Lake
Thousand Island Lake July 9, 2018
Near Agnew Meadows to Thousand Island Lake
Shadow Lake in hanging valley above deeply glaciated canyon of San Joaquin River with Mt. Ritter and Banner Peak in center right.
Near Agnew Meadows to Thousand Island Lake
Hiking through fields of flowers. The Minarets are on the left followed by Mt. Ritter, Banner Pk. and Mt. Davis. The falls from Shadow Lake are in the center. You can just barely see the lake.
Near Agnew Meadows to Thousand Island Lake
Looking from High Trail across the upper portion of the San Joaquin River Canyon.
Near Agnew Meadows to Thousand Island Lake
San Joaquin River as it runs out of Thousand Island Lake

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Agnew Meadows to Thousand Island Lake

4.9 (10 Ratings)
Breath-taking views, lots of flowers, orange and golden rocks, great campsites; it does not get any better than this.
15.7
mi
Distance
3,094
ft
Gain
strenuous
Difficulty
Commonly BackpackedLakeRiver/CreekViewsWaterfallWildflowers
Access Issues
Overnight trips require a wilderness permit. Quota for trailheads (reserved-walk-in): High Trail 20 (12-8), River Trail 30 (18-12). These are very popular trails -- make reservations well in advance at: www.recreation.gov. Select Inyo National Forest Wilderness permits. Walk-in permits issued starting at 11:00 AM the day before your trip. They can be obtained at the Mammoth Lakes Visitor Center or the Mono Basin Visitor Center in Lee Vining. No permit required for long (15-mile) rxhs.

Route Details

Flatter
Steeper
15.75mi
Distance
3,094ft
Elevation Gain
3,094ft
Elevation Loss
30%
Max Grade
9,880ft
High Point
8,335ft
Low Point
Path Type
There and Back
Description
The trailhead is across from the first parking lot in Agnew Meadows, just past the pack station, about 0.2 miles from the shuttle stop. The first 3 miles of the trail are a moderately steep climb from 8,360 to 9,690 feet. In the early season (as late as August 1st in 2019), there are numerous small stream crossings and several places with water running down the trail. This is no problem if you have waterproof boots, but otherwise, your feet will get wet. The trail starts by switchbacking for about 0.6 miles, through a red fir forest, up a draw created by several small creeks. It then traverses a very green and flowery open area. At 1 mile, the trail leaves the draw, and we get our first views across the glaciated canyon on the San Joaquin River. Much of the Ritter Range is already in view. Mt Ritter and Banner Peak dominate every view throughout the region. Looking down the canyon, you can see Mammoth Mt., the Mammoth Crest, and the Silver Divide. At this 1-mile point, we come to the first of the rocks to the left of the trail that have level areas that can be used as spectacular campsites. There are several more of these scattered along the next 3 miles. Campfires are allowed for the first 5 miles, and, at least until mid-season, fresh water is never very far awayFrom the 1-mile point, the trail climbs through the forest until about the 3-mile point, where it comes to a vista point directly across the canyon from Shadow Lake. Shadow sits in a U-shaped hanging valley carved by a tributary glacier. At this point, the San Joaquin Canyon, carved by the main glacier, is 700 feet lower. You can see and hear the large stream cascading down from Shadow Lake. The Minarets are just coming into view. Lake Ediza is hidden in the back of the valley behind Shadow Lake. The main climbing is now behind us. From here, there are ups and downs, but a total of only about 500 feet of climbing. For the next 2.5 miles, the trail traverses open areas with low, deep green bushes, plenty of flowers, and spectacular views the entire way. Looking up the canyon, Thousand Island Lake is hidden by small rounded domes at the end of the canyon. You can see the complex terrain that the trail needs to cross to get there. At 5.4 miles, we come to the junction with the trail going to Summit Lake and Agnew Pass. Although it is slightly out of the way, there is a great group campsite on rocks above the south end of Summit Lake. It has views down the entire length of the canyon and on to the mountains beyond. However, the High Trail takes the left fork and drops down 200 feet over the next 0.7 miles to where it crosses the trail that connects Agnew Pass and the River Trail. This is probably mostly used by pack trains. The High Trail makes a gentle climb up to Badger Lakes. The trail to the largest Badger Lake is unmarked, but obvious. That lake has a quiet, pleasant campsite. About 0.2 miles from Badger Lakes, we come to a trail coming from Clark Lakes. In another 0.4 miles, we pass the River Trail and begin the 200-foot climb to Thousand Island Lake. Most of the climbing is in the first 0.5 miles. After that, the trail follows a tiny stream to the San Joaquin River, just below the lake. The official source of the San Joaquin River is a permanent (at least before climate change) snow field above the longest of the stream flowing into Thousand Island Lake. It is 369 miles by river from there to the river's end in the San Francisco Bay.

Route Conditions

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Contributors
Amy Hikesalot