Oregon Revised Statutes Highways, Roads, Bridges and Ferries § 368.720

(1) The county governing body of any county may expend any portion of the funds apportioned to it from its share of funds derived under the Oregon motor vehicle law, or any other county money provided by law to be used in road construction, for the construction, maintenance and repair of streets, roads and highways in the state outside of the county.

(2) All such work of construction, maintenance or repair shall be done under an intergovernmental agreement that sets forth the terms under which the funds may be used and the party to the agreement that is responsible for the direction, supervision and maintenance of the work.