Columbia river would be my guess.

Explains the Cooper's ferry evidence in Idaho [1].

I hear there is oral tradition from the coastal and Oregon tribes about the glacial "Missoula floods" which took place repeatedly between 10k-20k years ago.

[1] https://www.seattletimes.com/seattle-news/artifacts-in-idaho...

I don't have the references, but I know that there have been some discoveries in Latin America and Western South America, that have been very old. Probably not "solid" enough for many scientists, though.

> Humans traveling over ice sheets from eurasia to the americas never made a huge amount of sense when they could skirt it's resource-rich edges - and traveling by water is much faster, and much less calorically intensive than traveling by land. You also have your food readily available.

... No-one is suggesting people traveling over ice sheets? In fact, the primary reason for the conventional chronology is that it avoids any ice sheets.

During the last glacial maximum, the sea level was low enough that the entirety of Beringia was above sealevel. It was also not covered by ice, and it was one of the richest places for hunter-gatherers to live north of the tropics. Think less of a land bridge and more of a continent. This allowed access to western and central Alaska, but the way forwards was blocked by the Laurentide ice sheet, both on the continent and extending significantly over the ocean. For someone to cross from Alaska to the southern part of the continent, they would have to sail over 2000km without access to anything but deep ocean and floating ice.