I noticed that the Seattle Chess Club was getting close to having 1000 events listed on the USCF website. CLICK HERE The USCF records listed on the website only start in 1991. So the clubs listed below have run lots more events but to get those numbers would take searching of NORTHWESTS CHESS magazines.
As of March 25, 2015, affiliates checked:
Seattle Chess Club 994 events
Portland Chess Club 985 events
Spokane Chess Club 546 events
Tacoma Chess Club 285 events
Washington Chess Federation 216 events
Oregon Chess Federation 38 events
Usually an event is a tournament of some kind but matches between two players count also as an event. Other things that one can find on the USCF website in another place are the number of events a person has directed. Fred Kleist of Seattle has 2209 sections in 850 events.