I first visited Thousand Island Lake in the summer of 1958 while on a two week backpack loop from Yosemite Valley. I visited it again in 1959, 1960, 1966, 1977, 1980, 1988, and 1991. On the map, my routes of travel (which overlap in many places) are shown in various colors as identified below.
1958 Yosemite Loop Trip (red map line)
This was my first trip on the John Muir Trail. I covered the section from Yosemite Valley to Thousand Island Lake.
From the beginning of the John Muir Trail at Happy Isles in Yosemite National Park I hiked the Muir trail to Tuolumne Meadows, then south over Donohue Pass to Thousand Island Lake.
I then turned west on a cross-country route over Lake Catherine Pass north of Banner Peak and worked my way to the Merced River headwaters then followed the river back to Yosemite Valley.
1959 Silver Lake to Pine Creek Trip (green map line)
This was my second trip on the John Muir Trail. I covered the section from Thousand Island Lake to Hilgard Branch of Bear Creek.
I started at Silver Lake on the June Lake loop ... up the steep trail ... across the tramway used for the power company dams to camp at Clark Lakes near Agnew Pass. Beautiful sunset. Continued to Thousand Island Lake with continuously changing views of Banner and Ritter peaks.
I then hiked the John Muir Trail south to the Hilgard Branch of Bear Creek. I followed the Hilgard Branch up to Lake Italy, then out over Italy Pass to the trailhead on Pine Creek where I hitch hiked back to my car at Silver Lake.
1960 Banner Peak Climb (yellow map line)
In 1960 I climbed Banner Peak from Lake Ediza with a San Diego Sierra Club group. Although we didn't camp at Thousand Island Lake, we had great views of it from the top of Banner Peak.
1966 Yosemite to Red's Meadow Explorer Post 360 Trek (purple map line)
In August 1966, Explorer Post 360, of which I was the adult Advisor, backpacked the John Muir Trail from Yosemite Valley to Reds Meadow on our annual "Sierra Trek".
1977 Memorial Weekend Trip (white map line)
Some friends from Independence and I backpacked from Silver Lake via Agnew Lake, Spooky Meadow and Clark Lakes to Thousand Island Lake. We didn't have much trouble with snow and made good time. Thousand Island Lake was still mostly frozen. Part of the party climbed Mt. Ritter via Ritter Lake. Gordon Lee and I started out to climb Mt. Davis but ended up on a peak unofficially named "Mullberry Peak".
1980 Fourth of July Weekend Trip (white map line)
Jimmy White and I backpacked from Silver Lake to Agnew Lake, then took the Spooky Meadow/Clark Lakes route to Thousand Island Lake. There was quite a bit of snow around and Thousand Island Lake was still mostly frozen. We took it easy and enjoyed the solitude.
1988 Marie Lakes - Davis Lakes Loop Trip (blue map line)
In 1988 I did a nine day backpack from Agnew Meadows trailhead. I took the High Trail to Thousand Island Lake where I explored the area on two layover a days. Then hiked cross country to Island Pass and followed the John Muir/Pacific Crest Trail north toward Donohue Pass to the junction with a trail to Marie Lakes. On August 22, 1988 .. my birthday .. I arrived at the Marie Lakes located just southwest of Donohue Pass in the Ansel Adams Wilderness.
I stayed two days at Marie Lakes, exploring the upper lake and enjoying the solitude and scenery. Then I proceeded cross country parallelling the Ritter Range past Rodgers Lakes to Davis Lakes for two more nights. Then proceeded near Island Pass to the upper end of Thousand Island Lake and on to a small lake above Garnet Lake, eventually returning to my car at Agnew Meadows.
1991 Devil's Post Pile - Agnew Meadow Loop Trip (black map line)
Gil Beilke and I backpacked from Devil's Post Pile National Monument along the west ("back") side of the Ritter Range via Hemlock Crossing to Twin Island Lakes, then over Lake Catherine Pass to Thousand Island Lake and out at Agnew Meadows.
The following pictures are in the Thousand Island Lake area:
Agnew Meadows Approach
The approach from Agnew Meadows on the Devil's Postpile road via the High Trail, which is also the Pacific Crest Trail (the John Muir Trail uses a different route here), offers views of Mt. Ritter, Banner Peak and Shadow Lake.
Instead of taking the High Trail from Agnew Meadows you can take the trail to Shadow Lake ... then north on the John Muir Trail ... you can also get great views from the top of Banner Peak which dominates the area.
There is a saddle between Mt. Ritter and Banner Peak which can be ascended via a snow slope from either Lake Ediza on the south or Lake Catherine on the north.
Silver Lake Approach
The route from Silver Lake, on the June Lake Loop road, via Clark Lakes is usually the only reasonable access early in the season .. Memorial Day and Fourth of July weekends.
Tuolumne Meadows Approach
The John Muir and Pacific Crest Trails lead from Tuolumne Meadows in Yosemite National Park south over Donohue Pass and Island Pass to Thousand Island Lake. Banner Peak is the pointy peak in front, Mt. Ritter is behind.
Hemlock Meadow Crossing Approach
You can approach Thousand Island Lake from the west via a trail that goes north from Hemlock Crossing to a meadow below Twin Island Lakes. A low grade trail and "ducked" route, left over from early days when there was a mine claim in the area, leads up to Lake Catherine from which a pass leads to Thousand Island Lake. You can also climb to the Ritter-Banner saddle from here.
Thousand Island Lake and Banner Peak Views
At Thousand Island Lake there are many fine views of the lake and Banner Peak.
Stitched panorama of Banner Peak over ice covered Thousand Island Lake, Mt. Davis, Rogers Peak, Mt. Lyell