I've never seen any mountain lions around Seattle, but definitly lots of cougars.
True story though, my buddy was hunting elk around the big hole in MT and at the end of the morning hunt he was tired and hungry. He was headed home empty handed when he heard some strange noises coming from a clump of aspens. He goes over there and there's a mountain lion that just backed off a fresh elk kill growling at him. My buddy takes out his hunting knife and cuts a hind 1/4 off the cougar's elk kill and runs away, with dinner!!