The Wynoochee River is a 60-mile long river located in the Olympic Peninsula in the U.S. state of Washington. The name Wynoochee comes from the Lower Chehalis placename /xʷənúɬč/, meaning "shifting". A tributary of the Chehalis River, the Wynoochee River rises in the Olympic Mountains within the Olympic National Park and flows generally sout…The Wynoochee River is a 60-mile long river located in the Olympic Peninsula in the U.S. state of Washington. The name Wynoochee comes from the Lower Chehalis placename /xʷənúɬč/, meaning "shifting". A tributary of the Chehalis River, the Wynoochee River rises in the Olympic Mountains within the Olympic National Park and flows generally south. Its drainage basin is 218 square miles in area.