Saint Helens
- Country: United States
- State: Oregon
- Population: 13,526 (2016)
- Latitude: 45° 51.8' N (45.864°)
- Longitude: 122° 48.4' W (-122.80649°)
- Elevation: 26 m/85 ft. above sea level
- Time zone: America/Los_Angeles (UTC -08:00); DST observed (UTC -07:00)
- Alternate names: Casenau, Houlton, Kasenau, Milton, Plymouth, St. Helens