The ancestors of living Native Americans arrived in what is now the United States at least 15,000 years ago, possibly much earlier, from Asia via Beringia. A vast variety of peoples, societies and cultures subsequently developed. European colonization of the Americas, which began in 1492, resulted in a precipitous decline in Native American population because of new diseases, wars, ethnic cleansing, and enslavement. After its formation, the United States, as part of its policy of settler colonialism, continued to wage war and perpetrated massacres against many Native American peoples, removed them from their ancestral lands, and subjected them to one-sided treaties and to discriminatory government policies, later focused on forced assimilation, into the 20th century. Since the 1960s, Native American self-determination movements have resulted in positive changes to the lives of many Native Americans, though there are still many contemporary issues faced by them. Today, there are over five million Native Americans in the United States, 78% of whom live outside reservations: California, Arizona and Oklahoma have the largest populations of Native Americans in the United States. Most Native Americans live in small towns or rural areas.
