Specimen Mountain is a 12,494-foot summit in northern Colorado's Front Range, just north of Milner Pass in Rocky Mountain National Park. More than a high peak, it is the eroded remnant of an ancient, red-tinted volcano whose last eruptions occurred about 27 million years ago. Once likely taller and more conical, it was worn down over time to its present form. Traces of that volcanic history remain nearby in yellowish ash exposed in roadcuts near Poudre Lake. Also known historically as Geode Mountain and Mountain Smokes, it had its present recorded name by 1932 and stands out among the region's more typically granitic, glaciated peaks.