Elevation: 5,556 ft
This peak is not found in the book.
Casner Mountain is located south of Warm Springs Point and southwest of Idaho City and northeast of the confluence on Mores Creek and Grimes Creek, the two major drainages in the southwestern Boise Mountains. You have to options to reach the peak.
If you are also planning ascending Warm Springs Point approach Casner Mountain from the north by following the Centerville Road northwest from Idaho City for 3.8 miles and the turn left onto FS-311. Follow FS-311 south for roughly 8.25 miles to the point where FS-311 begins its descent to ID-21. At this point you are due north of the summit. If you want to access the peak more directly FS-311 can also be accessed from ID-21 at the confluence of Mores Creek and Grimes Creek. Turn off of ID-21 onto the Grimes Creek Road and then immediately turn right onto FS-311. Follow the road as it climbs up to the ridge top directly north of Casner Mountain. FS-311 is a steep, narrow and road road but does not necessitate a 4WD when dry. Check with the Forest Service for current conditions.
From FS-311 north of the peak an old, brushy road can be followed to the base of the summit. From this point if you look carefully you can spot a skid road climbing up toward the top. This route climbs roughly 250 feet in 0.7 mile to the summit. Class 1+
USGS Warm Springs Point
Climber Trip Reports