Before the explorations in the 15^th century, Native Americans lived freely and undisturbed in the Western Hemisphere, from the Arctic to Tierra del Fuego. 

In the 11^th century, however, the Vikings were the first explorers who landed in New Foundland, then four centuries later, in 1492 Columbus came to the New World, which started the real time of explorations throughout the American continent. The undisturbed way of life ended and Native Americans have never had the same peace again anywhere in the Americas.

By the time of the Columbus voyage in 1492, variation in the physical appearance of the American Indians was minimal in comparison with their tremendous variations in language, lifestyle, and other aspects of culture. To some extent, this variation reflects diversity in their Asian origins but mostly represents successful adaptation to the diverse environments within the Americas. Their numbers in North America, including Eskimo or Inuit and Aleut, in 1492 had likely grown to 2 million or more. 

The new culture contact initiated by Columbus not only brought profound cultural change to the Americas but introduced a variety of Old World diseases as well. Tragically, the number of Indians was greatly reduced by about 1900.

In 1870, the 9^th U.S. Census was the first to recognize Indians as a separate "race" and attempt to count them. After reaching a demographic low in the late nineteenth or early twentieth century, the Native American population has once again demonstrated resilience and adaptability and approached their number in 1492 in North America.

Even many years after the beginning of explorations, the U.S. government was still fighting against the Indians in many ways. There were five general patterns of Indian displacement:

1. drift, in which tribes migrated away from white settlements by choice, or sometimes toward them;

2. banishment, in which tribes were prevented from entering certain areas;

3. relocation, in which tribes were forcibly moved to a new region;

4. concentration, in which tribes were forced to live in a smaller part of their existing territory; and

5. extinction, in which tribes were either obliterated through disease and warfare, or assimilated within the white population.

United States territorial expansion meant Indian territorial reduction. Every white territorial thrust had its own set of consequences among differing elements of the native population, changing lives and history, the end result being diminishing of the vast aboriginal land base to a present-day size of a mere 52 million acres, less than the state of Minnesota. As a result, the story of Indian land cessions within what has evolved into the continental United States is immense and intricate, each region of the country, each tribe, and each period of history having its own chronicle.