Northwest Region of the United States Pony Clubs
This helpful site lists all clubs in the region, includes a calendar of USPC events, and downloadable forms/documents.

USPC (United States Pony Clubs, Inc.)

USPC Guidelines for D1-C2 Ratings

USPC Guidelines for H/B-A Ratings

USEA (United States Eventing Association) 

USEA VII EVENTING (OR, WA, MT, ID, AK) 

Lake Washington Saddle Club

Equestrians Institute

Hollywood Hill Saddle Club