The earliest architects in North America built elaborate burial mounds in the Ohio Valley.

When a large number of burial mounds were found in the Ohio River drainage and other parts of eastern North America in the nineteenth century, the ancestors of native North Americans seemed an unlikely source for their grandeur to the European mind. Various non-Indian mound builders were hypothesized: the lost tribes of Israel, the Vikings, and other Old World groups. The oversight of Native Americans is surprising, given the high culture developed by the Native Americans in Mexico and Peru. In fact, other hypotheses suggested that the Mound Builders were an offshoot of, or ancestral to, these Middle American cultures, but few explanations allowed for a relationship to North American Indians. Late in the nineteenth century, however, careful studies by the Smithsonian Institution’s Bureau of Ethnology demonstrated that the mounds were built by ancestors of the historic North American tribes.

Although it is not yet possible to determine how the builders of such elaborate structures, presumably sedentary agriculturalists of high culture, developed, or how they gave rise to the more mobile, and seemingly less highly cultured, natives encountered by European pioneers, there is much known about the Mound Builders, and reasonable hypotheses for their origin and relationship to the historic Indian tribes have been developed. Most evidence suggests that the original natives of North and South America were members of Siberian tribes that crossed the Bering Strait from Siberia to Alaska some time after 13,000 b.c.e. This was during the early stages of the last glacial retreat, when the Bering Strait was dry land. These tribes were big-game hunters who moved south into North, Central, and South America as the ice sheets melted. These people, called Paleo-Indians, moved into the eastern part of North America and came to live in sparse, wide-ranging populations in the forests that developed there after the glacier melted.

Archaeologists recognize a second Native American culture, the Archaic, beginning about 6000 b.c.e. Directly descended from Paleo-Indians, the Archaic Indians are thought to have given rise to the Mound Builders around 700 b.c.e. Some Late Archaic woodland groups buried their dead in small, natural hills, and a few built small burial mounds, the presumed progenitors of the more elaborate burial mounds built by the Woodland Indians. The larger burial mounds are widespread throughout eastern North America but are centered in the Ohio River drainage.

The earliest of the Ohio River Mound Builders were the Adena and are thought to have lived between 700 b.c.e. and 200 c.e. Their culture is characterized by the development of fiber-tempered pottery, domestication of several kinds of native plants, and the development of elaborate rituals and practices for burying their dead, including the mounds in which they were buried. They also worked stone to make pipes and various ornaments. In addition to cultivating plants, they gathered wild plant products and hunted available animals. They used a spear-throwing device called an atlatl (developed by Archaic or late Paleo-Indians) to produce greater flight speed in their spears. They added burials to individual mounds through time and were more sedentary than their Archaic predecessors. There is evidence that trading networks developed between the Adena people and contemporaneous American Indian cultures.

The Adena gave rise to the Hopewell culture, which was also centered in the valleys of the Ohio River and its tributaries. The Ohio Hopewell culture is recognized from around 100 b.c.e. until about 400 or 500 c.e. The Hopewell tradition is characterized by advanced pottery production and stoneworking, more intensive cultivation of native plants, some cultivation of corn (Zea mays, ultimately obtained from Mexico), and more elaborate funeral procedures and burial mounds.

Although corn was grown by the Hopewell people, it was not the staple it became in Middle American and Mississippian cultures. Instead, corn seemed to be grown more for symbolic and religious ceremonies. There is some anthropological evidence that the Hopewell people’s more diversified diet, based on the cultivation of several native plant species and supplemented by hunting and gathering, produced a healthier population than did the corn-intensive diet of the Mississippians.

The Hopewell Indians also developed vast, nearly continent-wide trading networks. This trade may have been associated with another cultural development that differentiates the Hopewell from the Adena. Researchers have hypothesized that some Hopewell men obtained privileged positions in society because of their trading skill and trade contacts. These men were buried with more elaborate material goods and in larger and more complex mounds than were other members of the population. As a result, Hopewell burials suggest a class structure not seen in the more egalitarian Adena burials.

Adena and Hopewell mounds were built by people carrying baskets full of dirt from a source region, called a borrow pit, and depositing the dirt on the growing mound. Large mounds with many burials were built in stages, with one set of burials superposed on an earlier group. Many artifacts, presumably prized possessions and tools needed for the next life, were buried with the dead. More of these are found in Hopewell burials than in Adena burials. The Hopewell differentiation of class, and contrasting Adena egalitarianism, are hypothesized on the basis of such artifacts and specific conditions of the burials.

Hopewell characteristics are all elaborations of Adena characteristics. It is impossible to determine the point in time at which the Adena culture ended and the Hopewell began; instead, there is a lengthy transition period. Clearly, the Hopewell tradition is a continuation of the Adena culture.

The Hopewell culture peaked in the Ohio River Valley around 200 c.e., and their mound-building activities, at least, disappeared between 400 and 500 c.e. Numerous hypotheses have been proposed for the decline of Hopewellian peoples, at least as Mound Builders. The theories range from an environmental catastrophe, brought on by larger population concentrations and intensive agriculture, to changes in trade balances that brought an end to the Hopewell people’s strategic central position between the northern and southern and between the eastern and western sources of raw materials and finished goods.

The last North American mound-building culture, the Mississippian, was centered along the Mississippi River at Cahokia, where East St. Louis, Illinois, now stands. It developed around 700 c.e. and flourished until after 1500. Adena and Hopewell mounds were primarily burial mounds, but many Mississippian mounds were platforms on which temples, houses, and other structures were built. Many scholars believe that these Mississippian Mound Builders were descendants of the Hopewell through intermediates who, for unknown reasons, abandoned mound-building activities. Many also believe that the Mississippians were directly ancestral to the Cherokee, Sioux, and other historic American Indian tribes. Some researchers posit that Hopewellians were ancestral to the Iroquois.

The Ohio Valley Mound Builders maintained a developing culture for more than a millennium and played a central role in North American prehistory for much of that time. Their descendants gave rise to the prehistoric Mississippian culture and to historic Indian tribes. In addition, North American archaeology traces its professional roots to the exploration of their mounds.

• Fagan, Brian M. Ancient North America: The Archeology of a Continent. 2d ed. New York: Thames and Hudson, 1995. Describes the Mound Builders and their place in prehistory. Chapter 2 gives a brief history of the European Mound Builder hypothesis. Illustrations, maps, index, and bibliography.
• Shaffer, Lynda Norene. Native Americans Before 1492: The Moundbuilding Centers of the Eastern Woodlands. Armonk, N.Y.: M. E. Sharpe, 1992. Explores Mound Builder cultures and the interactions and interrelationships between those cultures and other Native American cultures. Illustrations, maps, index, and bibliography.
• Silverberg, Robert. The Mound Builders. Athens: Ohio University Press, 1970. Discusses the hypothesis that the Mound Builders were European, and its demise. Also describes the American Indian Mound Builder cultures. Illustrations, maps, index, and bibliography.
• Snow, Dean R. The Archaeology of North America. New York: Chelsea House, 1989. Outlines the prehistory of the Mound Builders. Chapter 1 covers the Mound Builder mystery and its importance in American archaeology. Illustrations, maps, index, glossary, and bibliography.
• Thomas, Cyrus. Report on the Mound Explorations of the Bureau of Ethnology. 1894. Reprint. Washington, D.C.: Smithsonian Institution Press, 1985. Describes the Bureau of Ethnology’s mound work. The introduction to the 1985 edition adds historical perspective. Illustrations, maps, and index.
• Webb, William S., and Charles E. Snow. The Adena People. Knoxville: University of Tennessee Press, 1974. Descriptions of the mounds, pottery, pipes, and other artifacts of the Adena and Hopewell people. Illustrations, maps, index, and bibliography.
• Woodward, Susan L., and Jerry N. McDonald. Indian Mounds of the Middle Ohio Valley: A Guide to Adena and Hopewell Sites. Blacksburg, Va.: McDonald and Woodward, 1986. A guide to Adena and Hopewell sites that can be visited by the public. Illustrations, maps, index, and lists of pertinent topographic maps and publications.