During the 19th century America expanded its territories from the Atlantic ocean to the Pacific ocean, developing its own true national identity. When they came into these new lands, the first originally inhabitants were the American Indians, a population of nomadic people who based their lives and economy on hunting, agriculture and fishing. They were divided into many distinct numerous tribes or/and ethnic groups.
So since the end of the 15th century, when European started migrating to america, there tribes had many conflicts with the new inhabitants: old and new society clashed (because of the differences between the two types of values and cultures).
For example, many tribes of american Indians kept their hunting grounds and agricultural lands shared through their entire tribe.
The europeans made the exact contrary, their lives were based on the idea of individual propriety, and that caused the main problem with american tribes, that's because while they moved from one territory to another, basing themselves on the seasons, europeans occupied territories, preventing american tribes to come back there the year after.
Another difference is that American Indians lived in contact with nature, respecting the lands and te resources.
The most relevant american Indian tribes were:
They all extremely respected the eldest members of their community, because they represented wisdom and experience, while for the European communities the attention was given to the young generations.
All cultural and social differences caused series of continuous conflicts which ended after the battle of Funded Knee, when the last Indian leader Geronimo (Apache's leader) surrendered. After that the Indians were confined into reservations, where they still live today.