Final answer:
Early peoples most likely migrated to North America over the Bering Land Bridge, with genetic and archaeological evidence supporting multiple migration events from Asia. Alternate theories, such as the Solutrean hypothesis and coastal migration theory, compliment the primary understanding of a complex migration history.
Step-by-step explanation:
Most archaeologists believe that early peoples crossed into North America over a land bridge known as Beringia, which connected Asia and North America during the last ice age. This Bering Land Bridge migration model suggests that human migration took place in waves, and was followed by the megafauna of the Pleistocene era. Current genetic studies support the theory of migrations from Asia, showing mitochondrial DNA (mtDNA) and DNA haplogroups evidence of such movements, starting around 30,000 years before present.
Alternative theories such as the controversial Solutrean hypothesis posit a European origin from the Solutrean culture. However, this hypothesis lacks genetic evidence and is not widely accepted. Another more credible theory is the coastal migration, or Pacific sea travel, also known as the kelp highway hypothesis, suggesting that people followed the continental coastline southward, living off marine resources.
Ultimately, many historians and archaeologists now agree that human migration to the Americas was a multifaceted process that occurred both over land through Beringia and by boat along the coast. The combination of archaeological, genetic, and linguistic evidence supports the coexistence of multiple migration theories over a long span of time.