After the Last Glacial Maximum, North Eurasian populations migrated to the Americas about 20,000 years ago. Northern Eurasia was peopled after 12,000 years ago, in the beginning Holocene. Arctic Canada and Greenland were reached by the Paleo-Eskimoexpansion around 4,000 years ago. Finally, Polynesia was peopled after 2,000 years ago, by the Austronesian expansion
(Source from the Wikipedia. Hope this helps!)