Elevation: 10,162 ft
Climbing information for this peak is found on page 305.
Rainbow Mountain is not the most imposing Lemhi peak when viewed from the valley but is an enjoyable climb via it’s Southeast Ridge Route and a challenging Class 4 climb via it’s northeast face.
Southeast Ridge Route. (Class 2)
This is a shorter and steeper route than the routes described in the book. Drive midway between Coal Kiln Spring and Box Spring on the two track that parallels the crest to the small drainage that comes off the peak’s sest side. Climb due west at first through sagebrush and then trees heading toward Point 9883 and the crest of the Southeast Ridge. Follow the ridge to the summit in 3,600 feet.
Northeast Face, (Class 4)
Larry Prescott climbed Rainbow Mountain from the Coal Kiln Road and the peak’s east face. Turn left off of ID-28 at the signed road for the Kilns and follow the road past the Kilns, proceeding as far as your vehicle will allow. From the end of the road, a trail leads to a basin at the base of the northeast face.
Larry reported “I decided to take a more challenging route up the face directly to the summit. The crux was finding a route through the tall cliff band guarding the face. Making the route even more difficult was a few inches of snow.” Larry rated the route through the cliff band Class 3-4. Based on his photos, I would rate the route a solid 4. Use the link below to read Larry’s trip report.