The name given to the skeletal remains of a prehistoric man found on a bank of the Columbia River in Kennewick, Washington, USA on July 28, 1996. The remains had been scattered in the reservoir due to erosion. Following delivery of the cranium by the coroner, they were examined by archaeologist James Chatters. After ten visits to the site, Chatters had managed to collect 350 bones and pieces of bone, which with the skull completed almost an entire skeleton. The cranium was fully intact with all the teeth that had been present at the time of death. All major bones were found, except the sternum and a few bones of the hands and feet. The remains were determined to be those of "a male of late middle age (40-55 years), and tall (170 to 176 cm), slender build". Many of the bones however, were broken into several pieces. At the University of California at Riverside, a small bone fragment was subjected to radiocarbon dating. This fixed the age of the skeleton at approximately 8,400 radiocarbon years or 9,300 calendar years.

The biological diversity among ancient skulls in the Americas has further complicated attempts to establish how closely Kennewick Man is related to any modern Native American tribes. Skulls older than 8,000 years old have been found to possess greater physical diversity than do those of modern Native Americans. This range implies that there was a genetic shift in populations about 8,000 years ago. The heterogeneity of these early people shows that genetic drift had already occured, meaning the racial type represented by Kennewick Man had been in existence for a considerable period of time.

 The discovery of Kennewick Man, along with other ancient skeletons, has furthered scientific debate over the exact origin and history of early Native American people. The prevailing hypothesis holds that a single wave of migration occurred, consisting of hunters and gatherers following large herds of game, which wandered across the Bering land bridge around 12,000 years ago.

To be of practical use in a historical context, some argue further that the term "Native American" should be applied so that it spans the entire range from the Clovis culture (which cannot be positively assigned to any contemporary tribal group) to the Métis, a group of mixed ancestry who only came into being as a consequence of European contact, yet constitute a distinct cultural entity.

Anthropologists and archaeologists are now finding evidence that people lived in the Americas much earlier, maybe 20,000 or even 30,000 years ago. There are also signs that humans lived on the Pacific Coast of South America before the last ice age. Could the first ‘americans’ have arrived in northern america from Asia and worked their way south by boat? Some researchers also see a resemblance between early American and European stone tools. Did some of the first Americans come from across the Atlantic Ocean, millenia before the Vikings who established settlements in Labrador and ‘new found land.’ a thousand years ago?

These are some of the questions scientists hope Kennewick Man can help answer. They say he holds clues about his physical traits, health, and lifestyle that can lead to a better understanding of the first Americans.