ORS § 105.605
Any person claiming an interest or estate in real property not in the actual possession of another may maintain a suit in equity against another who claims an adverse interest or estate therein for the purpose of determining such conflicting or adverse claims, interests or estates. Any municipal corporation or county of this state claiming any interest or estate in real property which is not in the actual possession of another, including real property acquired by foreclosure of delinquent tax liens situated in the same county, may maintain a suit in equity against all persons who claim an adverse interest or estate in all or any part of the property for the purpose of determining the conflicting or adverse claims, interests or estates. One or more parcels may be included in one suit and the issue made by the pleadings in any suit by a municipality or county relating only to a certain parcel or part of the real property, shall be separately tried and determined upon motion of any interested party.
ORS 105.605