Cahokia, a Mississippian city, held more than 20,000 people by 1250 CE
Centuries before Europeans arrived, people on the Mississippi were building Cahokia, a mound city of over 20,000. Estimates for the pre-contact population of the modern United States run from 2 million to more than 18 million. By the end of the 1700s, disease, war and genocide had cut it to roughly 600,000.
Archaeology points to arrivals via Beringia, the land bridge from Siberia to Alaska, starting about 25,000 years ago and continuing until around 12,000 years ago, with some groups perhaps paddling earlier along a coastal Kelp Highway. Clovis and Folsom hunters are known from their distinctive spear points. Earthworks at Watson Brake and Poverty Point date to 3500 BCE and 2200 BCE, and Hopewell trade later linked the Eastern Woodlands with the Great Lakes and the Gulf of Mexico before the Mississippian culture raised its urban centres.
Contact from the late 15th century brought diseases such as smallpox, and some regions lost 90 percent or more of their people within a century. Ethnographers group the continent's peoples into ten cultural areas, many holding land in common, a practice alien to European ideas of property. After independence, George Washington and Henry Knox pushed a policy of assimilation, and the Indian Removal Act of 1830 drove nations west of the Mississippi on forced marches like the Trail of Tears.
The legal relationship shifted several times. Early treaties treated tribes as semi-independent nations until the Indian Appropriations Act of 1871 reclassified them as domestic dependent nations, while leaving much sovereignty intact, which is why many reservations still sit outside state law. The Indian Citizenship Act of 1924 made all US-born Native Americans citizens, though some states kept them from voting for decades. Service in World War II, the American Indian Movement and the Self-Determination and Education Assistance Act of 1975 opened the way to Native-run schools and greater tribal control.
Counting is complicated. In the 2020 census, 3.7 million people reported American Indian or Alaska Native ancestry alone and 5.9 million in combination with other groups. Cherokee is the largest self-reported tribe by a wide margin, ahead of Navajo. Self-identification only began in 1960; earlier, the census taker decided a person's race.
Source: Native Americans in the United States
