The Baker (City) Tower in Baker City, Oregon since its construction in 1929 has been heralded as the tallest building east of the Cascades Mountains crest in Oregon at 144 feet. Perhaps a few grain elevators are in the same height league around the region, but as a habitat storeyed structure minus any aeriels or media gear on top, the Tower is the tallest.
Just this season, the new Wildhorse Hotel was just topped off north of Pendleton, Oregon as part of a casino complex on the Umatilla Indian Reservation. I don't know how tall the building is, but I wonder if it's the second-tallest...
(all photos taken by Mellotrongirl with a Nikon Coolpix S-320 and are hosted via flickr.com)