Who was John Day?

There are many places in Oregon named after John Day.... he has a river, a town, a national monument, a forest, and a dam. And those are the places we have been to or seen on the map. We have been wondering who this amazing man might be- he must have been pretty special to have all of those namesakes! Our theories were "one of the first explorers here" or perhaps "the man who discovered fossils here". Not quite.... At the park yesterday we learned that John Day was a trapper who came west and was robbed by the Indians. They took everything, including his clothes! The spot where he was found and saved was on the way to one of the trading forts. Passersby mentioned the incident frequently until the river that forked at the site was eventually called John Day River. The rest came after that. Lesson for the day.... if you want stuff named after you, get robbed and make it a good story!