Heart Mountain is an 8,123-foot (2,476 m) klippe just north of Cody in the U.S. state of Wyoming, rising from the floor of the Bighorn Basin. The mountain is composed of limestone and dolomite of Ordovician through Mississippian age, but it rests on the Willwood Formation, rocks that are about 55 million years old—the rocks on the summit of Heart Mountain are almost 300 million years older than the rocks at the base. For over one hundred years, geologists have tried to understand how these older rocks came to rest on much younger strata.

Cody is a city in and the county seat of Park County, Wyoming, United States. It is named after Buffalo Bill Cody for his part in the founding of Cody in 1896.