Città di Stati Uniti, comincia con la lettera O Pagina 5
- Oak Grove (Ohio County)
- Oradell
- Oakdale (Suffolk County)
- Oakdale (Allen Parish)
- Oak Brook
- Old Town
- Oak Grove (Jackson County)
- Oakdale (Allen Parish)
- Osceola
- Olivette
- Oak Hill (Fayette County, West Virginia)
- Oak Grove (Christian County, Kentucky)
- Ojai
- Orono (Hennepin County)
- Ormond-by-the-Sea
- Othello
- Orland
- Oceano
- Odessa (Pasco County)
- Orland Hills
- Ocean City (Worcester County)
- Orange Lake
- Old Jefferson
- Oasis
- Orchard Mesa
- Oak Island
- Contea di Ontonagon
- Ogden (New Hanover County)
- Orting
- Oyster Bay
- Opp
- Oakland (Fayette County, Tennessee)
- Old Greenwich
- Oneonta (Blount County, Alabama)
- Osceola County (Iowa)
- Oelwein
- Oakmont
- Ontario (Richland County)
- Otis Orchards-East Farms
- Oak Ridge (Guilford County)
- Ohio County (Indiana)
- Orlovista
- Oxford (Worcester County)
- Osprey
- Ottawa County (Kansas)
- Orange City (Sioux County)
- Opal Cliffs
- Oceanport
- Old Tappan
- Oreland