At Medicine Lodge, petroglyphs and pictographs preserve some of the only known records created by earlier people, with some believed to be as old as 2500 years. The site contains nearly every recorded rock art figure type of the northwestern plains, whether pecked, incised, or painted, and its diversity and quantity make it one of the region's major rock art localities. Archeologists believe early hunter-gatherers living here during the Late Prehistoric Period, 1,500 to 150 years ago, created most of the petroglyphs, while ancestors of local tribes including the Crow and Shoshone made more recent rock art during the 1700s and late 1800s. Thousands of images line the sandstone cliffs, often layered over earlier figures, and fully pecked figures such as bighorn sheep are believed to be the oldest petroglyphs at Medicine Lodge. Rock art at such sites is often revered as sacred by the people who created it, their descendants, and others who have visited.