Ontario 987 Ohio 824 Oregon 450 Oceania 429 OECD countries 407 Oklahoma 230 Oxford 228 Outer space 187 Oxford (England) 149 Ohio River Valley 121 Orient 101 Oakland 65 Oman 63 Oceania Region 62 Oaxaca (State) 59 Ozark Mountains 47 Oaxaca (Mexico : State) 42 Oxfordshire (England) 39 Oaxaca Valley 36 Oakland (Calif.) 33 Old Southwest 33 Oregon Territory 33 Oaxaca Valley (Mexico) 29 Ohio River 26 Odesa 25 Ostia (Extinct city) 25 Odesa (Ukraine) 24 Ottawa 24 Oaxaca 23 Old Northwest 23 Okinawa-ken 22 Orange County 22 Odisha 21 Oxfordshire 21 Orkney (Scotland) 18 Ohio River Region 17 Okinawa-ken (Japan) 17 Océanie 15 Osteuropa 15 Oregon National Historic Trail 14 Ostend (Belgium) 14 Ozark Mountains Region 14 Oaxaca de Juárez 13 Oberlin 13 Oaxaca de Juárez (Mexico) 12 Odisha (India) 12 Okinawa Island 12 Omaha 12 Orkney 12 Orlando 12 Oslo 12 Ottawa (Ont.) 12 Oak Park 11 Oklahoma City 11 Ontario (Canada) 11 Ostasien 11 Oahu 10 Oak Park (Ill.) 10 Olympic National Park (Wash.) 10 Oost-Azië 10 Osaka 10 Osaka (Japan) 10 Ontwikkelingslanden 9 Orange County (Calif.) 9 Orvieto 9 Oahu (Hawaii) 8 Oder-Neisse Line (Germany and Poland) 8 Ontario, Northern 8 Ontario, Southern 8 Oost-Europa 8 Oświęcim 8 Oaxaca (Mexique ; vallée) 7 Oberlin (Ohio) 7 Oceanië 7 Okinawa Island (Japan) 7 Ontario (Province) 7 Ontario, Lake (N.Y. and Ont.) 7 Orangeburg 7 Oxford (Miss.) 7 Oak Ridge 6 Occident 6 Olduvai Gorge 6 Olympic National Park 6 Omaha (Neb.) 6 Oneida County 6 Otavalo (Ecuador) 6 Owens Valley 6 Oyotunji African Village (S.C.) 6 Oaxaca (Mexique) 5 Oceana County 5 Oceana County (Mich.) 5 Ogallala Aquifer 5 Olympia (Ancient sanctuary) 5 Olynthus (Extinct city) 5 Oran 5 Oriente 5 Orinoco River (Venezuela and Colombia) 5 Orinoco River Valley (Venezuela and Colombia) 5 Orlando (Fla.) 5 Orvieto (Italy) 5