Out here, there's one in Coeur d'Alene, and one in Spokane that was new this year. I did them both. (There might be others, but I don't think so - the only other local races I know of are sprints and one Half-Iron)
The Coeur d'Alene is a lake swim, a relatively hilly bike (some sustained climbing), and a pretty much flat run. It's pretty well ran and popular with the locals. I think everyone who does Olympic distance triathlons that lives here does this race. Unless they hate hills.
The Spokane is a "lake" swim (it's actually a reservoir on the river but they call it a lake), a rolling bike (climbs, but not really sustained), and a flat run on mostly dirt (not technical trail, just paths in the dirt through trees). Their website leads me to believe they'll be doing it again next year - though after the race some guy that lives local to the lake sent in water samples and found toxic algae bloom levels thousands of times over the safe limit.

It was pretty well-ran for a first-time race, though small.
http://www.cdatriathlon.com (August 7, 2010)
http://www.spokanetriathlon.com (no announcement about 2010, but it was September 13 this year)
Aaaand that's the extent of my local knowledge
