What Is The Oldest North American Mound?

By Dr. Greg Little

Portions of this article come from The Illustrated Encyclopedia of Native American Mounds & Earthworks. The most consistent question I’m asked about American mounds is “which one is the oldest?” The fact is that the answer changes because American archaeology makes ongoing progress and keeps uncovering more and more. Since the 1950’s the answer was that the oldest mound was at Poverty Point, Louisiana. Until the 1990’s or so, it was thought that the first mounds were erected at the massive Poverty Point site as early as 1800 BC—or 3800-years ago. But some archaeologists argued for a more recent date of Poverty Point, about 1600 BC. In 1997 the oldest mound site distinction went to a site about 50-miles from Poverty Point, at Watson Brake, located near Monroe, Louisiana. Over 100 carbon dates were obtained from Watson Brake from samples that were taken from various locations in the 22-acre, 11-mound complex. The resulting dates centered on 3200 BC as the time that Watson Brake was constructed. Watson Brake is privately owned and is closed to the public, but its unexpected age led to more research at Poverty Point, which eventually was shown to be older than previously thought. Presently, there are specific mounds and earthworks at Poverty Point that date to as old as 3700 BC, making it the oldest known mound site—again.

Poverty Point

Poverty Point is a huge complex of earthworks and mounds with the earthworks arranged around what is believed to be massive bird effigy mound. This mound is 72-feet tall and measures 640-feet from wing tip to wing tip and is 710-feet from the head to the tail. A semi-octagonal (C-shaped) earthwork centers on the base of the bird mound. This earthwork is made from 5 to 7 ridges of earthen embankments that are 6-feet high and 80-feet wide. They C-shaped embankments run just under a half-mile in length and are thought to have been used as elevated platforms for houses. Poverty Point is also used as a term to describe a culture that was centered in the region and over 50 associated sites have been found in Louisiana, Mississippi, and Arkansas. The people of this culture made distinctive clay balls and cube artifacts that were used for cooking and other purposes. It is known that an extensive trade network was in operation at Poverty Point extending from the Gulf of Mexico to as far north as Missouri and Tennessee. In essence, around 5,700-years ago, a cultural group that constructed mounds and earthworks emerged in a wide-ranging region centered in Louisiana. This culture was probably the same one that made circular shell mounds along coastal areas on the Gulf and Atlantic. It is thought that there are probably older shell mounds now submerged along coastal areas.

Poverty Point’s Lower Jackson Mound

About 2-miles south of the center of the Poverty Point complex a single conical mound sits in a private cotton field. This mound is known as the Lower Jackson Mound and was once thought to be part of the site. The mound is 8-feet tall and 130-feet in diameter. While portions of the mound were destroyed by farming, a small historic cemetery was placed on its summit which essentially preserved the site. In the 2000’s the Lower Jackson Mound was shown to date to about 3500-3700 BC then predating the Watson Brake site by several hundred years. Poverty Point archaeologists then began collecting samples from an area in the effigy mound where erosion had caused problems. Carbon testing from this are surprisingly showed that construction of the effigy mound started around 3400 BC. Thus, the Lower Jackson Mound at Poverty Point is presently the oldest American mound, but it appears to be contemporary with early earth construction at the main Poverty Point complex. In coming years there will, no doubt, be a change in the answer to the question, “what is America’s oldest mound?”