Medicine Wheel/Medicine Mountain National Historic Landmark, Stone ceremonial structure in Big Horn County, United States

The Medicine Wheel/Medicine Mountain is a circular stone structure of local white limestone on a limestone bedrock near the summit of Medicine Mountain. It has a rim 80 feet in diameter, 28 spokes running from the rim to a central cairn about 10 feet across, and six smaller cairns at or near the rim. Low upright slabs form the outer ring, with flat stones between them.

The structure was built over a thousand years ago and likely served both astronomical observation and spiritual purposes for successive generations of indigenous peoples. It received National Historic Landmark status in 1970 and gained expanded protection covering roughly 4080 acres in 2011.

The Crow call the wheel Annáshisee, "Large campsite", and say it stood before they entered the region; the Arapaho name it Hiieeinoonotii, and Paul Moss gave a detailed account of Arapaho ceremonial use in 1993. Crow elder Tom Yellowtail told how Burnt Face built a wheel in the Bighorns after the Little People healed his face. No tribe publicly claims to have built the wheel, yet many nations treat it as sacred.

The wheel sits at 9,642 feet on the west summit of Medicine Mountain, about 35 km east of Lovell. A wide, deeply cut ancient travois trail leads directly up from the Bighorn Basin. In winter, when the asphalt road is snow-covered and closed, the old trail can still be walked from Five Springs Campground.

Studies show that the stone arrangement aligns with specific celestial events, including sunrise at summer and winter solstice and the rise of certain bright stars. These alignments suggest that earlier builders incorporated astronomical knowledge into the design.