Elevation: 9,045 ft
This peak is not in the book.
Jumpoff Peak is the highest point in a group of mountains that comprise the southern end of the Lost River Range. This peanut shaped group which stretches from east of Arco to north of Howe, Idaho is arguably a subgroup of the the Lost River Range. The western end is named the Arco Hills. There are 15 points which have at least 300 feet of prominence. This group has minimal forest cover and is penetrated by roads in many spots. There are no trails but the roads offer good routes for hardy hikers and tough mountain bikers. USGS Howe
Most visitors to this subrange come to hunt, ride ATVs and dirt bikes or maintain the two electronics facilities (on Jumpoff Peak and Howe Peak). The two high peaks are accessed via Eightmile Canyon over a steep road that tops out around 7,100 feet at a broad saddle. See the GPS track below. It takes 4.8 miles and 2,500 feet to reach this point from ID-33. I recommend a 4WD but friends drove the road in their Subaru and only suffered one flat tire.
From the broad saddle between Jumpoff Peak and Howe Peak you can drive to the lower, eastern summit of Jumpoff Peak and then hike to the true summit which will be a 0.5 mile trek or you can hike from the saddle which will be a 5.6 mile round trip. The road will,also make a good mountain bike ride. The surrounding country is big and open and enjoyable to walk. From the eastern summit to the true summit there are a couple of rock ribs to negotiate.