This is not a Chipmunk, chipmunks have dark stripes on their head and face.
Named after the golden-colored fur around its shoulders, as if it were wearing a shawl, the Golden-mantled Ground Squirrel (Callospermophilus lateralis) is a common resident throughout the Rocky Mountains at elevations between 5,000 and 11,000 feet above sea level. Right now, they are getting ready for their long hibernation and this one was searching among fallen pine trees for cones and seeds.