River with O
- Ohio river
- Oder
- Ottawa
- Oklahoma
- Oklahoma river
- Odra
- orinoco
- Orlando river
- Olga
- Obey river
- obed river
- Otay
- olive
- Otter Creek
- Osage
- Oak Orchard River
- Olympus
- Otay River
- ottawa river
- orion
- Ottowa
- Orinoko
- Orljava
- Omaha river
- Onyx
- Owl
- Otto
- Oka
- Ovens
- Ocoee
- Oswego
- Obed
- Olt
- One
- ophelia
- oregan river
- oman river
- ozark
- olympia
- Ogden
- Oneida
- Oker
- Okavango
- oval river
- orwell
- Ottowa River
- olivia
- old
- omar
- oxe
- orange county river
- Oise
- over
- Ober
- Oil
- olentangy
- only
- Ouse river
- Onions
- omaha
- Olly
- oolong
- olan
- ona
- owen
- Okechobee
- osiris
- Ostsee
- Okanogan
- Obion River
- OREGON
- Oyster
- Opera
The words in the list River with O come from players of the word game City, Country, River.