Oregon Revised Statutes Commercial Fishing and Fisheries § 511.011

The “mouth” of any river emptying into the Pacific Ocean including the bay or tidal area formed by each such river is the seaward end of the jetty or jetties of each such river. If no jetties exist, the extension of the Pacific Ocean, shoreline high watermark across the river, bay or tidal area, is the “mouth” of such river.