Cities of United States starting with letter O Page 10
- Oran
- Oglala
- Owensville (Gibson County, Indiana)
- Oley
- Ola
- Ogunquit
- Oxford (Oxford County)
- Onancock
- Otterbein
- Old River-Winfree
- Oakland (Burt County)
- Olcott
- Oakland (Sumter County)
- Omega
- Okarche
- Oneida (Brown County)
- Olmito
- Okeene
- Oolitic
- Ohatchee
- Orford
- Oxford (Benton County, Indiana)
- Oologah
- Ore City
- Ohkay Owingeh
- Osceola Mills
- Obion
- Occidental
- Oskaloosa (Jefferson County, Kansas)
- Oyster Creek
- Ogden Dunes
- Oxford (Warren County)
- Ordway
- Odin
- Oakfield (Fond du Lac County)
- Otisville
- Overbrook
- Oakland (Marshall County, Oklahoma)
- Oxford (Sumner County)
- Odell (Livingston County, Illinois)
- Omaha (Morris County, Texas)
- Odebolt
- Oilton
- Otego
- Oil City (Caddo Parish)
- Ouray
- Ottoville
- Owyhee
- Ocracoke
- Osceola (Saint Clair County)