The First Peoples

The land that would become the United States was not empty when Europeans arrived. It had been home to human beings for at least 15,000 years, and possibly much longer. Archaeological evidence suggests the first peoples migrated from Asia across the Bering Land Bridge during the last Ice Age, spreading gradually southward and eastward across the continent over thousands of years. By the time European explorers arrived in the late 1400s, North America was home to millions of people living in hundreds of distinct nations, speaking hundreds of different languages, and organized into a vast range of political, social, and economic systems.

These were not simple or primitive societies. Across the continent, indigenous peoples had developed sophisticated agriculture, extensive trade networks, complex governance systems, monumental architecture, astronomy, medicine, and rich artistic and spiritual traditions. The Mississippian city of Cahokia, near present-day St. Louis, had a population of perhaps 20,000 people at its peak around 1100 CE, larger than London at the same time. The Haudenosaunee Confederacy in the Northeast had developed a sophisticated system of representative governance centuries before Europeans arrived.

How long people have been here keeps moving further back. The older "Clovis first" model, which placed the earliest arrivals around 13,000 years ago, has been overturned by sites such as Monte Verde in Chile, dated to roughly 14,500 years ago, and by fossilized human footprints at White Sands National Park in New Mexico that the U.S. Geological Survey and National Park Service dated in 2021 to between about 21,000 and 23,000 years ago. Many archaeologists now think the first peoples moved south along the Pacific coast as well as through an inland ice-free corridor. The languages spoken at contact fell into dozens of unrelated families, among them Algic, Iroquoian, Siouan, Uto-Aztecan, and Na-Dene, a diversity comparable to that of the entire Old World.

Ways of life varied as widely as the land itself. Peoples of the Pacific Northwest built cedar-plank houses and carved monumental art along a coast rich in salmon. Ancestral Puebloan communities in the Southwest raised multistory stone towns such as Mesa Verde and linked Chaco Canyon to outlying settlements by a network of engineered roads. Across the Eastern Woodlands, farmers planted the interdependent "Three Sisters" of maize, beans, and squash, and peoples throughout the continent used controlled fire to clear underbrush, improve hunting, and shape the forests that Europeans would later mistake for untouched wilderness. Estimates of the population living in the area of the present-day United States at contact commonly range from about two million to seven million or more.

Major Indigenous Civilizations and Peoples

European Exploration and Early Contact

Sustained European contact with the Americas began in 1492 when Christopher Columbus, sailing for the Crown of Castile, reached the Caribbean. He made four voyages but never set foot on the North American mainland, making landfall instead in the Bahamas, the Greater Antilles, and the coasts of Central and South America. In 1494 the Treaty of Tordesillas divided the non-Christian world between Spain and Portugal along a line in the Atlantic, a division other European powers, including England and France, would simply ignore.

What followed is what the historian Alfred Crosby named the Columbian Exchange: a two-way transfer of crops, animals, and microbes. Wheat, rice, horses, cattle, and pigs crossed to the Americas, while maize, potatoes, tomatoes, cacao, and tobacco crossed to Europe, Africa, and Asia, reshaping diets and populations worldwide. The potato alone is credited with helping drive later population growth across northern Europe.

The exchange of disease was catastrophic and one-sided. Smallpox, measles, influenza, and typhus, to which Native populations had no acquired immunity, moved along trade routes and often ran ahead of Europeans themselves. Estimates of the pre-contact population of the Americas range widely, but a 2019 study led by researchers at University College London put it near 56 million in 1492 and estimated a roughly 90 percent decline by 1600, a loss so vast that the regrowth of abandoned farmland may have pulled enough carbon from the atmosphere to cool the global climate.

This collapse, not European numbers or technology alone, is central to how small colonial footholds later expanded. Depopulation emptied villages and cleared fields that arriving settlers described as wilderness or as providentially vacated for them. The Massachusetts Bay governor John Winthrop explicitly read the die-off among coastal peoples as God making "room" for the Puritans. The "empty" continent that colonization narratives assumed was in large part a recently emptied one.

What Gave England the "Right" to Colonize?

The legal basis for European colonization rested on what is now called the Doctrine of Discovery. Its roots lie in a series of fifteenth-century papal bulls: Dum Diversas in 1452 and Romanus Pontifex in 1455 authorized the Portuguese Crown to subdue and enslave "Saracens, pagans and other enemies of Christ," and Inter Caetera in 1493 drew Spain's line of claim across the Atlantic. Protestant England rejected the pope's authority but kept the underlying premise that Christian nations could acquire sovereignty over lands held by non-Christians.

England added its own twist. It claimed title by "discovery" made real through settlement and the "improvement" of land, and colonists invoked the idea of vacuum domicilium, John Winthrop's phrase, arguing that Native peoples who did not farm in the European manner or hold land as individual property had only a "natural" and not a "civil" right to it. Royal charters, from the Virginia Company's in 1606 to the Massachusetts Bay charter of 1629, granted English subjects the right to settle and govern with no mention of the consent of the people already there.

That premise passed directly into American law. In Johnson v. M'Intosh in 1823, Chief Justice John Marshall held that European discovery gave the discovering sovereign, and the United States as its successor, exclusive title, leaving Native nations only a right of "occupancy" that the federal government alone could extinguish. Marshall built on the same reasoning in Cherokee Nation v. Georgia in 1831, describing tribes as "domestic dependent nations."

Johnson v. M'Intosh has never been overruled. Justice Ruth Bader Ginsburg invoked the discovery doctrine in City of Sherrill v. Oneida Indian Nation in 2005, and the Court's 2023 decision in Haaland v. Brackeen left the broader framework of federal Indian law intact. Separately, on March 30, 2023, the Vatican formally repudiated the "Doctrine of Discovery" as no part of Catholic teaching, a symbolic step with no effect on United States law.