Cities of United States starting with letter O Page 17
- Oswego (Sumter County)
- Ovando
- Olowalu
- Ocean Beach
- Oasis (Millard County)
- Oneida (Nemaha County)
- Olivet (Hutchinson County, South Dakota)
- Oakville (Napa County)
- Orchard (Mitchell County, Iowa)
- Oscarville
- Olivet (Osage County)
- Oak
- Oketo
- Oakwood (Dewey County, Oklahoma)
- Ortley
- Orient (Faulk County)
- Oak Springs
- Oakhaven
- Ong
- Octa
- Ohiopyle
- Osterdock
- Oxbow (Aroostook County)
- Ottosen
- Orogrande
- Old Eucha
- Old Station
- Oakley (Lincoln County, Wyoming)
- Oneida (Delaware County, Iowa)
- Osgood (Sullivan County)
- Oxford (Franklin County, Idaho)
- Outlook (Sheridan County)
- Orin
- Owasa
- Ophir (Tooele County)
- Okaton
- Ocean
- Oasis (Elko County)
- Otranto
- Oak Hill (Wilcox County)
- Oak Hill (Clay County, Kansas)
- Obert
- Orrin
- Overly
- Oak Grove (Pawnee County)
- Onaka
- Odanah
- Ola (Brule County)
- Owl Creek
- Orange Blossom Trailer Park