The Headwaters 10k is a fast, flat counter-clockwise loop around Lake Siskiyou. The course is entirely on the Lake Siskiyou recreation trail. Incredible views of the lake backdropped by Mt. Shasta and Mt. Eddy abound.
The Headwaters 50k course is a scenic, loop-type course through the Klamath Mountains of Northern California, west of Mt. Shasta.