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