Three Creek Lake, tucked under Tam McArthur Rim, is a good place for a summer swim, especially if you have an inflatable raft to prevent full-body immersion in the often quite cold water. A tiny lakeside store rents rowboats; from the center of the lake you’ll get a good view of Tam McArthur Rim, named for the original author of the classic and fascinating reference book Oregon Geographic Names.
From the lake, trails lead into the Three Sisters Wilderness Area. A trail leads up to the 7,700-foot rim, and from the top the views of the Three Sisters and Broken Top are quite astounding. Snows can be heavy (the lake itself is at 6,500 feet), so don’t count on hiking this trail before July.
A lakeside campground ($14, no drinking water) makes this a pleasant place to spend a couple of days in midsummer, but be forewarned that most return campers bring insect repellent.
To get to Three Creek Lake from Sisters [1], turn south on Elm Street, which becomes Forest Road 16. Follow Road 16 south about 17 miles to the lake. Be prepared for a couple of miles of fairly rough dirt road. During the winter, Road 16 between the lake and Sisters has a couple of Sno-Park areas that mark cross-country ski trails.
Links:
[1] http://www.moon.com/destinations/oregon/central-oregon/sisters