Royal River
General data
- Name: Royal River
- Water system: Atlantic Ocean
- Water type: River
- Progression: Casco Bay -> Gulf of Maine -> Atlantic Ocean -> Planet Earth
- Climates: Temperate
- Continents: North America
- Countries: United States of America
The Royal River is a small river, 39 miles (63 km) long, in southern Maine. The river originates in Sabbathday Lake in New Gloucester and flows northeasterly into Auburn and then southerly through New Gloucester (via the Royal River Reservoir), Gray and North Yarmouth into Casco Bay at Yarmouth.