when did they migrate to america?
17,000 years ago
Paleo-Indians
 The traditional theory holds that these early migrants moved into Beringia between eastern Siberia and present-day Alaska 17,000 years ago,at a time when the Quaternary glaciation significantly lowered sea levels.
what is referred as bull run river? It is a tributary of the Sandy River. where is it situated? U.S. state of Oregon who were its first inhabitants? Paleo-Indians how is the climate here? mild climate is it related to any energy producing project? UNANSWERABLE how is the above mentioned group of people classified? They  are generally classified by lithic reduction or lithic core "styles" and by regional adaptations.
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Paleo-Indians [SEP] Migration into the Americas
Researchers continue to study and discuss the specifics of Paleo-Indian migration to and throughout the Americas, including the exact dates and routes traveled. The traditional theory holds that these early migrants moved into Beringia between eastern Siberia and present-day Alaska 17,000 years ago,at a time when the Quaternary glaciation significantly lowered sea levels. These people are believed to have followed herds of now-extinct pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran ice sheets. An alternative proposed scenario involves migration - either on foot or using primitive boats - down the Pacific coast to South America. Evidence of the latter would since have been covered by a sea-level rise of more than a hundred meters following the end of the last glacial period.