The highest peak in the Elk Mountains, and the range's most approachable 14er — a Class 2 scramble up a distinctive ridge above Montezuma Basin.
From Aspen, take Colorado 82 northwest to the junction with the Ashcroft/Maroon Lake roads, go left, then immediately take the left fork onto Castle Creek Road. Follow it about 11.5 miles to the ghost town of Ashcroft, then 1.5 miles farther to a fork; the road becomes rough from here, and most passenger vehicles should park at the valley floor around 9,800 feet. On foot or by high-clearance vehicle, the road climbs into Montezuma Basin, passing the abandoned Montezuma Mine around 12,400 feet and ending near 12,800 feet as the basin opens up. From the road's end, a poorly marked, rocky trail heads left (southwest) toward Castle Peak's northeast ridge. Aim for the saddle in the ridge if the trail is hard to follow; steep talus leads to about 13,400 feet, above which the ridge mellows before steepening again for a final loose, steep pitch to the summit — watch for a false summit just below the true one.
Reverse the ridge and basin. Many climbers continue from Castle's summit across to neighboring Conundrum Peak (under a mile away, descending to a saddle around 13,800 feet and back up), which adds real time and loose terrain to the day.