The coastal migration hypothesis is one of two possibilities in the settlement of the Americas at the time of the Last Glacial Maximum.It proposes a migration route involving watercraft, via the Kurile island chain, along the coast of Beringia and the archipelagos off the Alaskan-British Columbian coast, continuing down the coast to Central and South America.The alternative is the "interior route," which assumes migration along an ice-free corridor between the Laurentide and Cordilleran ice sheets during the Last Glacial Maximum.