Specimen Mountain, Mountain summit in Rocky Mountain National Park, United States

This mountain rises to about 12,500 feet in the Front Range of northern Colorado, where exposed volcanic rocks and alpine meadows dominate the landscape. The summit area displays clear geological layers and stone formations shaped by ancient volcanic activity.

Specimen Mountain is an extinct volcano that last erupted about 27 million years ago, when it was likely taller and more conical than today. It was recorded as Geode Mountain and Mountain Smokes before the name Specimen Mountain appeared in 1932. Yellowish ash from its eruptions is exposed in roadcuts near Poudre Lake.

The name Geode Mountain recalls the hollow, crystal-lined stones found on its slopes, and "Mountain Smokes" refers to the mist once seen rising from the summit. The peak appears on maps as Specimen Mountain by 1932. Roadcuts near Poudre Lake expose yellowish ash from its eruptions, a detail geologists stop to examine.

The main access is through established trails north of Milner Pass, where visitors should prepare for unpredictable mountain weather. Proper gear and attention to rapid weather changes are essential for a safe hike.

Red-tinted rocks and yellowish ash deposits near Poudre Lake reveal the mountain's volcanic origins in an unusually visible way. These colored layers are rare evidence of the geological transformations that shaped this peak.