Cities That Start With O

38 cities Places Checked 9 Oct 2026

These cities that start with O are the world's big cities with 300,000 or more people, 38 in all, ranked by population. A separate list covers 22 US cities that start with O, followed by capital cities.

O has 38 cities, so it is a middling letter. Osaka in Japan leads the size list, and Oslo and Ottawa are national capitals in Norway and Canada. Some O names are very short, like Oyo in Nigeria and Omsk in Russia, which suits beginners.

The US list includes Oklahoma City, Omaha in Nebraska and Orlando in Florida. Oyo is a palindrome, spelled the same backwards and forwards, which kids enjoy spotting. Short names like these are also handy in word-chain games.

Big cities starting with O: 38
Largest: Osaka Japan
Largest in the US: Oklahoma City Oklahoma

Cities that start with O around the world

#	City	Country	Population
1	Osaka	Japan	2.8 million
2	Ouagadougou	Burkina Faso	2.4 million
3	Ordos	China	1.9 million
4	Omdurman	Sudan	1.8 million
5	Onitsha	Nigeria	1.6 million
6	Omsk	Russia	1.2 million
7	Oslo	Norway	1.1 million
8	Ottawa	Canada	1.0 million
9	Odesa	Ukraine	1.0 million
10	Oran	Algeria	803,329
11	Ota	Japan	748,081
12	Oyo	Nigeria	736,072
13	Osasco	Brazil	728,615
14	Okayama	Japan	724,691
15	Oklahoma City	United States	681,054
16	Osogbo	Nigeria	645,000
17	odz	Poland	639,890
18	Orumiyeh	Iran	577,307
19	Orenburg	Russia	564,773
20	Owerri	Nigeria	545,000
21	Oujda	Morocco	539,711
22	Okara	Pakistan	533,693
23	Omaha	United States	486,051
24	Okene	Nigeria	479,178
25	Oita	Japan	477,715
26	Ogbomoso	Nigeria	433,030
27	Oakland	United States	419,267
28	Ojo de Agua	Mexico	386,290
29	Okazaki	Japan	384,654
30	Ondo	Nigeria	375,000
31	ong a	Vietnam	371,606
32	Olinda	Brazil	366,754
33	Otsu	Japan	345,070
34	Obalende	Nigeria	342,000
35	Orlando	United States	334,854
36	Oral	Kazakhstan	330,000
37	Osh	Kyrgyzstan	322,164
38	Orel	Russia	303,696

US cities that start with O

City	State	Population
Oklahoma City	Oklahoma	681,054
Omaha	Nebraska	486,051
Oakland	California	419,267
Orlando	Florida	334,854
Oxnard	California	207,254
Overland Park	Kansas	186,515
Oceanside	California	175,691
Ontario	California	171,214
Orange	California	140,992
Olathe	Kansas	134,305
Odessa	Texas	114,428
Orem	Utah	94,457
Ogden	Utah	85,444
O'Fallon	Missouri	85,040
Oshkosh	Wisconsin	66,555
Owensboro	Kentucky	59,042
Orland Park	Illinois	58,619
Ocala	Florida	58,218
Oak Lawn	Illinois	56,781
Olympia	Washington	55,733
Ozone Park	New York	53,985
Oak Park	Illinois	52,287

Capital cities that start with O

Capital	Country
Oslo	Norway
Ottawa	Canada
Ouagadougou	Burkina Faso

Questions people ask

What is the biggest city that starts with O?

Osaka in Japan, with about 2.8 million people in the GeoNames count.

What US cities start with O?

The largest are Oklahoma City, Oklahoma, Omaha, Nebraska, Oakland, California, Orlando, Florida, Oxnard, California.

What capital cities start with O?

Oslo (Norway), Ottawa (Canada), Ouagadougou (Burkina Faso).

Which country has the most big cities starting with O?

Nigeria, with 8 of the cities on this list.

Source: the GeoNames database: world cities with 300,000 or more people and US cities with 50,000 or more. Population figures are the latest GeoNames counts and can lag behind new census results.

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