The lake was formed about 20,000 years ago when rising magma-encountered groundwater resulting in violent steam explosions. The resulting explosions formed a broad shallow crater, which later filled with water. The lake covers an area of 99 acres with average depth of 33 feet with a maximum depth of 58 feet. South Twin Lake is a lure's toss from the Deschutes arm of Wickiup Reservoir and less than a mile south of North Twin lake.

The fishing at South Twin Lake has improved tremendously in the past few years after a 1987 poisoning by ODFW to eliminate rough fish. Consistent stocking of fingerlings and legal-size rainbow trout has resulted in an excellent fishery. The largest recorded rainbow to come out of South Twin was over 13.5 pounds. The trout average 10 to 14 inches, with 18-inch fish common.

Most anglers’ fish from boats and use bait. Depths of 15 to 30 feet are the best producers. Trolling slowly with a flasher and apiece of worm or egg or with a very small lure are productive methods throughout the season. Still fishing with eggs, worms, and a marshmallow or power bait far enough off the bottom to stay out of the weeds is also a popular method. Successful lures are Flatfish, Rooster Tails, small spoons, or small lures like Needlefish.

For best results, fly fishers use sinking or sink-tip lines and size 10 and 12 Hare's Bars, Twin Lakes Specials, or dark leech and streamer patterns. Nymph fishing is good all day around the edge of the lake. Make sure you try the shallows near the campground, too. The best fly hatches usually occur mid-day.

One more winning characteristic of South Twin Lake is its calm water when winds are howling over other Cascade lakes. South Twin is completely tree-lined except for the beach day-use area. Water levels vary little over the season. The lake is rich with weedbeds. No motors are allowed on the lake. Always check the current ODFW before fishing.

Basic Directions