The course is four races in one: a 20 mile "fun run", a 50k, a 50 miler and a 100k. All are described below:
All distances start and finish at Millpond County Park, five miles north of Bishop, California. All distances head through Millpond Campground before heading north then west around the Tungsten Hills, where the first aid station is encountered at mile 4. Climbing steadily on four wheel drive roads, the course continues up and around the main north west side of the Tungstens before briefly leveling out as the second aid station is neared at mile 9.8. After passing through the aid station, all distances turn right and again head uphill, towards Basin Mountain, Mount Tom, and the Buttermilk aid station at mile 11. The Buttermilk aid station is the turn around for the twenty mile fun run. (See below for the continuation of the description for the twenty mile course).
All other distances continue uphill on the Buttermilk Road, heading higher into the Eastern Sierra. The route stays on a rough, four wheel drive road and finally heads into a bit of forest as it nears McGee Creek aid station at mile 15. The course continues climbing to the busy Edison aid station at mile 17.4. This is the turn around for 50k racers. (See below for the continuation of the description for the 50k course). 50 milers and 100k runners must now do the famous Edison Loop, named after the various SCE power company's subtle hydro installations in the area. The course climbs steadily, with the occasional tree for cover, up to the top of the loop and a rustic aid station at mile 20.3 at 9,385' elevation. Reversing course, the first mile or so down from the course high point is the same as the uphill course, but shortly runners take a right turn and loop back down to the Edison aid station for a second visit. The course now climbs south, over a moraine and heads to well-stocked Intake 2 aid station at mile 26. Caution: the course crosses highway 168 here, where we will have crossing guards. Runners must not stop traffic.
Intake 2 marks the 26 mile point as runners now continue down through Forks Campground then up stream up the south fork of Bishop Creek on an old road, eventually crossing the road to South Lake. A fisherman's trail is followed to the turn around at Bishop Creek Lodge aid station and mile 29. Reversing course all the way back to Intake 2 runners finally get to enjoy a lengthy downhill. But after Intake 2 it's back up hill as the route heads back to the Edison Aid Station. Note that this is not quite an out and back as returning runners diverge from the earlier route for a couple of miles as they near the Edison Aid Station. The route now follows the outbound course, steadily downhill, past Mcgee Creek aid and then Buttermilk aid at mile 41. After Junction Aid station is reached for the second time (remember way back at mile 9.8?) the rest of the course is new ground, dropping pleasantly down to Highway 168 AS (mile 46.4) and eventually the Tungsten City AS (mile 48.5).
Here at mile 48.5 50 milers get to head right and finish it off with a pleasant run down sandy roads, through the Millpond Campground and the well appointed finish area.
100k runners, however, must make the famous left at Tungsten City, following a 6 mile (each way) out and back, through the Sage Summit Aid Station (miles 52.1 and 56.7), retrieve a poker chip so we know you've completed the course, and return back through Tungsten City and on to the finish.
There's a lot more info on the race specifics page.