This peak is not in the book.
Thatcher Peak is the northernmost Sawtooth Range peak. It is located due north of Copper Mountain. USGS Banner Summit

Access
Access the peak from the point where ID-21 makes a 110-degree turn at the base of the peak’s North Ridge.
North Ridge, Class 2
The North Ridge is a relatively straight shot to the summit. The only reported ascent was a Winter ascent. Read the linked trip reports below for additional details. It is 3.0 miles from ID-21 to the summit with 2,053 feet of elevation gain.

