Forks is named Forks because a group of rivers come together in this area.
Working from the shore to the mountains, here are the rivers:
1. Quillayute River. It is very short, only about four miles long.
2. The Dickey River empties into the Quillayute.
3. & 4. The Sol Duc River and the Bogachiel Rivers come together to form the Quillayute River.
5. Maxfield Creek empties in to the Bogachiel.
6. The Calawah River empties in to the Bogachiel. Open maps and follow the Bogachiel River way up in to the Olympic Mountains, and many other creeks and rivers empty in to it.
7. The Sol Duc River is paralleled by Olympic Highway 101, coming from the north and east, until Forest Service Road 2918. Then the source is from the south and east, up in the Olympic Mountains. There are myriad creeks and rivers that join it along the way. The origin is up close to the glaciers of the Olympic Mountains. Olympic National Park is huge. Jefferson County, Washington is mostly National Park and National Forest. You could hike across the county, but you have to drive either north or south to get to the other side. There is no road across the county. Olympic Highway is a loop around the peninsula. You can drive the entire loop in a long day as long as we are not having floods, mudslides, snow, earthquakes, a cyclone, a tsunami or other potential disasters.
Forks is named for the confluence of the five rivers. Looking at the western side of the Olympics, you can see how an average 110 inches of rain per year in Forks can cause massive floods, with the water falling all the way up into the mountains and then coming down and joining together over and over, carrying entire trees if the water is high.
Grundoon worked for the Forest Service in Port Angeles in the Olympic Mountains in the mid 1980s-90s. She wrote about how dangerous this park is for people who are not prepared. It can be very very wet and cold and sometimes freezing, and the way out to the road is not necessarily obvious. The park is big and very wild.