These races are point to point and take place predominantly on the Continental Divide Nation Scenic Trail (CDT) and the Continental Divide. The length of Continental Divide covered in this event also represents the boarder between Idaho and Montana. On the west side is Idahos Lemhi River Valley on the East is Montanas Big Hole Valley. In the 100K at mile 49, runners will leave the official CDT for the remainder of the course, but will continue along the true Continental Divide boarder for another 5 miles (mile 54). FYI, at mile 49 the CDT dips into Montana then turns parallel to the Continental Divide in-order to divert away from a section of hard to navigate terrain consisting of high mountains, scree, and cliffs. We as masochistic trial running RDs think you should experience some of the beautiful scree fields but not the cliffs, so we will drop off the Continental Divide at mile 54 and descend into the head waters of Bohannon Creek and onto the finish line. The 50K race covers the second half of the 100K race starting near the Lemhi Pass AS. Because runners following the Continental Divide [separation between drainage to the Pacific Ocean (Idaho side) and Atlantic Ocean (Montana side)] they will always be high in the mountains following the natural elevation changes along the divide and will not ascend or descend into the deep creek and river valleys that boarder the course, except when they drop off the divide to the finish. Because of this, the entire race is at a high elevation with respect to this part of Idaho and Montana. This course has a good mix of terrain, with a mix of climbs, descents, flats and technical sections. This race course has a little bit of every thing to please all types of runners. The 100K is a Western States 100 Qualifying Race. Both races are Ultra Trail du Mont Blanc qualifying races.