Both were formed around 20,000 years ago when a rising magma reservoir reached groundwater, creating violent steam explosions.

The largest recorded rainbow trout caught from South Twin Lake weighed over 13.5 pounds (6.1 kg).

South Twin Lake is completely tree-lined except for the beach day-use area.

[5] This article incorporates public domain material from South Twin Lake.

Media related to North and South Twin Lakes (Oregon) at Wikimedia Commons