A mound is a heaped pile of earth, gravel, sand, rocks, or debris. Most commonly, mounds are earthen formations such as hills and mountains, particularly if they appear artificial. A mound may be any rounded area of topographically higher elevation on any surface. Artificial mounds have been created for a variety of reasons throughout history, including habitation, ceremonial, burial (tumulus), and commemorative purposes.

Petroforms, also known as boulder outlines or boulder mosaics, are human-made shapes and patterns made by lining up large rocks on the open ground, often on quite level areas. Petroforms in North America were originally made by various Native American and First Nation tribes, who used various terms to describe them. Petroforms can also include a rock cairn or inukshuk, an upright monolith slab, a medicine wheel, a fire pit, a desert kite, sculpted boulders, or simply rocks lined up or stacked for various reasons. Old World petroforms include the Carnac stones and many other megalithic monuments.