A term used to describe the prehistoric Native Americans who constructed the burial and temple mounds that are widespread east of the Mississippi River. It was once thought to be a distinctive group of peoples, but now the mounds are assigned to the Hopewell and Adena cultures. Burial mounds were characteristic of the Indian cultures of east-central North America from about 1000 BC to 700 AD. The most numerous and grandly conceived ones, found in the Ohio and Mississippi river valleys, were large conical or elliptical mounds surrounded by extensive earthworks.