Colter Peak stands 10,683 feet high near the eastern boundary of Yellowstone. It is one of hundreds of peaks in the Absaroka Range, which extends from Livingston Peak near Livingston, Montana, to Ramshorn Peak near Dubois, Wyoming, 150 miles to the south. The Absaroka Range was created primarily by volcanic activity during the Eocene epoch 30 to 60 million years ago. The most recent reshaping of the landscape occurred when the Pinedale glacier covered virtually all of Yellowstone Park and extensive areas to the south and north, from Jackson, Wyoming, to Livingston, Montana. The gentle early morning fog that drifted up from the Southeast Arm of Yellowstone Lake contrasted with the massive and powerful forces which pushed this peak up, then scraped, bulldozed, and ground gigantic blocks from it to the plains and rivers below.