Simplify the following text for a Grade 8 native English-speaking person.
Original: The Kobuk River ( also Kooak , Kowak , Kubuk , Kuvuk , or Putnam ) is a river located in the Arctic region of northwestern Alaska in the United States .
Simplified: The Kobuk River ( also Kooak , Kowak , Kubuk , Kuvuk , or Putnam ) is a river that is in the Arctic region of Alaska , in the United States .