Ohio 41,553
Oregon 29,168
Ontario 24,981
Oklahoma 15,821
Oceania 10,991
Outer space 5,666
Oxford 5,010
OECD countries 4,982
Oman 4,320
Odisha 3,153
Orient 2,599
Okinawa-ken 2,485
Oxford (England) 2,290
Ohio River Valley 2,178
Okinawa-ken (Japan) 2,082
Orissa 2,065
Osaka 1,870
Oaxaca (State) 1,818
Orange County 1,706
Oakland 1,635
Ohio River 1,565
Oaxaca (Mexico : State) 1,396
Odisha (India) 1,372
Odesa 1,330
Osmanisches Reich 1,323
Osaka (Japan) 1,308
Orissa (India) 1,249
Odesa (Ukraine) 1,202
Oslo 1,054
Oaxaca 1,047
Oakland (Calif.) 1,013
Oxfordshire 898
Ottawa 881
Oxfordshire (England) 880
Oregon Territory 856
Okinawa Island 850
Osteuropa 814
Oregon National Historic Trail 752
Orkney (Scotland) 728
Ouganda 720
Ozark Mountains 667
Omaha 644
Old Northwest 639
Orkney 605
Oslo (Norway) 568
Österreich 565
Omaha (Neb.) 548
Ostfriesland 545
Odessa 539
Orange County (Calif.) 526
Ostfriesland (Germany) 508
Osaka (Prefecture) 499
Ostasien 494
Ottawa (Ont.) 483
Oahu 475
Oldenburg 466
Okayama-ken 465
Okinawa Island (Japan) 459
Oceania Region 453
Ostroh 451
Oklahoma City 449
Okayama-ken (Japan) 445
Osaka (Japan : Prefecture) 441
Onondaga County 414
Occident 399
Ohio River Region 398
Océanie 384
Oświęcim 377
Ontario, Lake (N.Y. and Ont.) 358
Oneida County 356
Old Southwest 335
Oświęcim 329
Oudh (India) 323
Omsk 321
Oklahoma City (Okla.) 308
Orvieto 306
Orange County (N.Y.) 293
Onondaga County (N.Y.) 292
Oudh 289
Ontario, Northern 286
Orenburgskai︠a︡ oblastʹ (Russia) 286
Ostia (Extinct city) 282
Orange 281
Oldenburg (Germany) 275
Oran 274
Orlovskai︠a︡ oblastʹ 274
Oran (Algeria) 272
Osnabrück (Germany) 272
Orléans 268
Oder-Neisse Line (Germany and Poland) 267
Orléans (France) 267
Oaxaca de Juárez (Mexico) 266
Orlando 265
Osnabrück 265
Omsk (Russia) 264
Oberpfalz 263
Olympic National Park (Wash.) 263
Olomouc 262
Oneida County (N.Y.) 253
Ozark Mountains Region 252