From OpenCarry.org - State Information For Oregon
"Oregon is a traditional open carry state. However, their preemption statute only covers concealed handgun license holders from city or county passed bans against loaded firearms in public places. To our knowledge, only the cities of Portland, Beaverton, Tigard, Oregon City, Salem, and Independence have passed loaded firearms bans encompassing all public places, and other cities have passed bans specific to Parks. Also, all 'public buildings' are also off limits throughout the entire state unless you have a concealed handgun license."