Depends on where you are coming from, and how long you're willing to travel, but the Westport Boat Basin is a great place to come salmon watching!
http://www.discoveringwestport.com/2...mon-derby.html
The local High School works with the Humptulips Hatchery and releases hatchlings every year, so there is a group (I don't know what you would call them) but some salmon who come back to the Boat Basin thinking that is where "home" is. The Chamber of Commerce sponsors a fishing derby, but you can also just stand out on the Fisherman's Boardwalk and watch the schools of salmon passing by. It's pretty cool. I like to eat at the Half Moon Bay Bar and Grill and watch the fishermen out on the docks.
My sister is bringing her kids down this weekend and we're going to take the kids fishing because its supposed to be good "catching" from now until the end of October.
Directions to the Westport Marina:
westhaven drive, westport, wa - Google Maps