While this timeline focuses on immigration and citizenship practices in the United States, human migrations to and within the Americas began long before European colonization.
There are many competing theories and beliefs about the peopling and of the Americas. One widely held theory is that the indigenous peoples of what we now call North and South America migrated from Siberia by way of the Bering Land Straight (also known as Beringia) roughly 20,000-30,000 years ago and then migrated further south over the course of many centuries. However this and competing theories are speculative and continuously evolving, due to discontinuities in evidence and weak dating methods. Moreover, this theory conflicts with the creation beliefs of some indigenous tribes. Numerous other pre-Columbian migrations are speculated to have originated from Polynesia, Africa, East Asia, and the Middle East. One notable migration includes a Norse settlement in modern-day Canada roughly half a century before Columbus landed in Hispaniola in 1492. Within the continents, many indigenous tribes practiced seasonal migration, moving for more abundant food and climate conditions.