Shirttail Peak is the highest point in Eldorado Canyon State Park in Colorado. With Eldorado Canyon being well known for its world-class rock climbing, Shirttail Peak is generally not thought of as a hiking destination. As of the year 2000 publishing of the Rock Climbing Eldorado Canyon guidebook by Richard Rossiter, there are 18 separate class 5 climbing routes on Shirttail Peak, ranging from 5.5 to 5.12a.
However, hiking to the summit from either the Eldorado Canyon Trail Trailhead or the Mesa South Trailhead does not involve any technical climbing.
The peak is characterized by its pyramidal summit which rises over an already-dramatic foundation of sheer rock walls that are popular with rock climbers. At the base of Shirttail Peak to the northwest resides the classic Rincon Wall, and farther down the ridge to the south is the ultra-classic Red Garden Wall.
Shirttail Peak is one of five named minor summits in the Boulder Group of peaks, the others being The Nebel Horn, Dinosaur Mountain, Flagstaff Mountain, and Mount Sanitas. Each of these peaks sits in the shadows of Boulder's major summits: Eldorado Mountain, South Boulder Peak, Bear Peak, and Green Mountain.
The peak is unranked when using the Colorado Summit Criterion because it has only 80 feet of prominence above the saddle connecting it with South Boulder Peak.
From the summit, one can dizzyingly peer off the south side almost straight down to the canyon floor 1400 feet below. One is also rewarded with great views of the Indian Peaks to the west, Eldorado Mountain to the south, the plains to the east, and South Boulder Peak to the north.