I believe I have discovered that place along the Pechanga Valley in NW Nikel Oblast near the Norway/Russia border.
Some of the earliest settlers in what is now the United States came from Nikel Oblast and were members of the Skolt Sa'ami tribe (which is down to 500 native speakers in the Old World, and may number as many as 2 million people in America ~ virtually none of whom know they are an ancient people called Skolt). Many settled around Nickel Mines Pennsylvania (and a gazillion other places with a Christmasy, or traditional Scandinavian motif name, e.g. Santa Claus, Christmas Valley, Deer Park, Elkins, Elkton, etc.)
Jedediah Smith would necessarily have had considerable contact with American Skolt.
Why I posted that bit of early settlement lore is because we face a similar problem with "Croatan" ~ a place named Croatan Island, a band of Indians at Croatan Island, next thing you know you have the Croatan Indians.
The Indians didn't name themselves Pechanga. The Indians didn't name themselves Croatan.
"River Avon" is yet another instance of this sort of thing ~ "Avon" means "river" in Welsh.
My mother's family came to North America from Sweden in the 1630s on the Kalmar Nyckel settling near what is now Philadelphia. A reproduction of the Kalmar Nyckel is currently moored in Delaware. Does the ship's name "Kalmar Nyckel" have anything to do with the region you mention -- Nikel Oblast?