Ancient tools discovered in Maryland show the first humans came to America 7,000 years earlier than previously thought

[wnylib]

5. The following article gives two time periods when

coastal routes would have been most favorable for boats along the Pacific Coast, based on core samples taken off the coast of Alaska. The samples go back 45,000 years to learn about climate and extent of glaciation at different times.

The article gives the two periods as 24,500 to 22,000 years ago and 16,400 to 14,800 years ago and makes a good case for arrival in the Americas by water instead of by land.

My opinion, not covered in the article, but based on conversations with the staff of archaeologist James Adovasio, is that the early Americans would have followed two routes, one southward along the coast to South America, and the other across the North American continent. The glaciers would still have been present along the area that is now the US-Canadian border, extending into present day US in some areas. Once the people were past the glaciers at the coast, they could flow streams and rivers inland, going eastward across North America just south of the glaciers.

The land along the southern border of the glaciers would have streams and lakes fed by glacial meltwater which would draw animals for hunting. The land would be grassy in some areas and swampy in others. Farther away from the glaciers there would be woodlands.

https://www.livescience.com/bering-land-bridge-was-only-passable-during-2-brief-windows-study-finds