Oregon Revised Statutes Highways, Roads, Bridges and Ferries § 366.285

(a) By reason of loss or destruction of field notes of the original surveys made by the county when such roads or highways were laid out and established by the county, defective or incomplete surveys or records, or destroyed monuments or marks, the exact original location and boundary cannot be found or ascertained.

(b) For any reason the exact location and right of way lines are in doubt or are challenged.