This loop is a Seattle-area classic, circumnavigating Granite Mountain in the Alpine Lakes Wilderness, just to the north of I-90 at exit 47. The trail links Melakwa Lake, Lower Tuscohatchie Lake, and Pratt Lake between the Denny Creek and Pratt Lake/Granite Mountain trailheads. The route is approximately 16.5 miles as a complete loop connecting the trailheads by road (3.5 mi on the road). It is commonly done both clockwise and counterclockwise, each presenting unique challenges in terms of grade and technicality (counterlockwise is generally considered the faster direction for most runners due to longer and less technical descents).
Trisha Steidl (F) claims to have run sub-3 (2:49 plus a couple short breaks) in the counter-clockwise direction. This was years ago and with no GPS or verification, but I have no reason not be believe her given her reputation for speed, honesty, and humility.