Anthropology

in the Americas are 1) Pacific coast Islands and 2) across North America from the Pacific to the Atlantic just south of where the glaciers reached.

If people entered the Americas by boat, which I think they did, some would have continued a southward movement along the Pacific Coast into South America while others moved inland along rivers, streams, and lakes that formed from meltwater just below the glaciers.

Some of the oldest sites suggest that kind of travel pattern, i.e. White Sands, NM and Meadowcroft Rockshelter in western PA just north of Pittsburgh. Now there is this possibility in the Chesapeake Bay area.

The oldest sites were probably covered by ocean water along the Pacific coast when water levels rose from melting glaciers, so islands off the coasts of Washington, Oregon, and California would be interesting places to search. Also, the Baja California peninsula, including the side facing the Gulf of California (aka Sea of Cortez) and the western coast of Mexico that borders the Gulf of California could be interesting places to look.