You are right, I apologize for bringing it up again. As for a different US demonym, I think Canada was named after a river (said river being renamed to
St Lawrence) so maybe it could be the same for the USA?
It's cool, and not directed at you. This has gone on for two pages, and it's an interesting discussion, so I'd hate for the mods to lock it since 'we can't have nice things.'
Canada is a Iroquoian name, but I'm not sure which group (using Iroquoian in the broader sense of including the Erie, Huron/Wendat, and other similar groups aside from the Iroquois/Haudenosaunee themselves). The Lenape, which had grip on much of what would become the middle colonies have a name for their homeland,
Lenapehoking. This could serve as a basis, whether they use the term itself or a corruption of it. Mexico, Guatemala, and Nicaragua are also examples of indigenous names becoming the name of future nations, so there's definitely a precedent for it.