6,162 articles
Omdurman
Omdurman (أم درمان) is Sudan's largest city by the 2008 census, on the west bank of the Nile opposite Khartoum. Mahdist State capital 1885–1898, site of Kitchener's 1898 battle, and a major battleground of the Sudan war since 2023.
Omsk (Омск)
Omsk (Омск), Siberian city at the Om-Irtysh confluence, administrative center of Omsk Oblast since 1934. Founded as a fortress in 1716 by Bukholts; city status 1782; population about 1.11 million; major oil-refining and petrochemical center on the Trans-Siberian Railway.
Ondo
Ondo: a state in southwestern Nigeria created in 1976, capital Akure, nicknamed the Sunshine State; also the historic Ondo Kingdom and its town Ode-Ondo, ruled by the Osemawe since 1516.
Onești
Onești, a municipality in Bacău County, Romania, in the Tazlău-Cașin depression; first attested 1458, industrial town built from 1952 around the Borzești petrochemical platform, population 51,012 in 2019.
Ongole
Ongole (ఒంగోలు) is a city and district headquarters in Prakasam district, Andhra Pradesh, India; a municipality since 1876 and municipal corporation since 2012, known for the Ongole cattle breed.
Onitsha
Onitsha is a port city on the eastern bank of the Niger River in Anambra State, Nigeria, home to the Onitsha Main Market, the largest market in Nigeria.
Ontario, California
Ontario, California: Inland Empire city in San Bernardino County founded 1882 by the Chaffey brothers as the Model Colony, incorporated 1891; population about 187,000, home to Ontario International Airport.
Ooty
Ooty (Udhagamandalam, உதகமண்டலம்) is a 2,203 m hill town and Nilgiris District capital in Tamil Nadu, India; a British summer capital reached by the UNESCO-listed rack railway from Mettupalayam.
Opa-locka, Florida
Opa-locka is a city in Miami-Dade County, Florida, founded May 14, 1926 by aviator Glenn Curtiss with architect Bernhardt Muller around an Arabian Nights theme, known for its Moorish Revival architecture, 20 National Register buildings, and 2020 population of 16,463.
Opština Vraneštica
Opština Vraneštica (Вранештица) was a small former municipality in western North Macedonia, seat at Vraneštica village; 109.13 km², 15 settlements, 1,322 inhabitants (2002), merged into Kičevo municipality in 2013.
Oradea
Oradea (Nagyvárad, Großwardein) is a municipality in north-western Romania, seat of Bihor County, first recorded in 1113 as Civitas Varadiensis, known for Art Nouveau architecture and a medieval fortress.
Orai
Orai (उरई) is a city in Uttar Pradesh, India, headquarters of Jalaun district in Bundelkhand on the Kanpur-Jhansi NH27; 2011 population 190,595, third largest city of Jhansi division.
Oral, Kazakhstan
Oral (Uralsk, formerly Yaitsky gorodok), city on the Ural River at the Chagan confluence in northwestern Kazakhstan, center of West Kazakhstan Region; founded 1613 by Yaik Cossacks, renamed 1775 after Pugachev's revolt; population about 234,000.
Oran (وَهْرَان)
Oran (وهران) is Algeria's second-largest city, a western Mediterranean port captured by Spain in 1509, held until 1792, taken by France in 1831, and the birthplace of raï music.
Orange, California
Orange, California: Orange County city founded 1871 as Richland, incorporated April 6, 1888; population 139,911 (2020); home to Old Towne Orange, the Plaza, and Chapman University.
Orange, New South Wales
Orange, NSW: regional city in the Central Tablelands, 254 km west of Sydney, on Wiradjuri land below Gaanha-bula (Mount Canobolas). Proclaimed a village in 1846; the 1851 Ophir gold discovery nearby began the Australian gold rush; population about 44,000.
Oranjestad, Aruba
Oranjestad (locally Playa) is the capital of Aruba, named in 1824 after the Dutch royal House of Orange following a gold discovery. Known for Fort Zoutman, the Willem III Tower, Port City redevelopment, and downtown revitalization.
Orchha (ओरछा)
Orchha (ओरछा), a historic town in Niwari district, Madhya Pradesh, on the Betwa River, was the Bundela dynasty capital 1531-1783, famed for Jahangir Mahal, Ram Raja Temple, and cenotaphs, and on India's UNESCO Tentative List since 2019.
Ordos City
Ordos City (鄂尔多斯市) is a prefecture-level city in southwest Inner Mongolia, China, a major coal and natural gas producer whose Kangbashi new district was famously labeled a "ghost city" by Al Jazeera and Time in 2009–2010.
Ordu (city)
Ordu, Black Sea coast city in Türkiye, seat of Ordu Province; ancient predecessor Kotyora (Bozukkale), visited by Xenophon c. 400 BC; modern city founded late 18th century; leading Turkish hazelnut center.
Örebro
Örebro is a city in central Sweden, seat of Örebro Municipality and County, founded in the 13th century around the Örebron bridge over Svartån. Hosted the 1810 Riksdag electing Bernadotte and the 1812 Treaty of Örebro; home to Örebro University.
Orem, Utah
Orem, Utah: city in Utah County on the eastern shore of Utah Lake, incorporated May 5, 1919 and named for railroad president Walter C. Orem. Fifth-largest Utah city, home of Utah Valley University, population about 95,000 in 2025.
Orenburg
Orenburg (Оренбург), Russian city on the Ural River and capital of Orenburg Oblast, founded 1743 as an imperial fortress; population about 551,000; hit by the record April 2024 flood after the Orsk dam breach.
Orihuela
Orihuela, in Valencian Oriola, is a municipality in the province of Alicante, Spain, capital of the comarca of Vega Baja del Segura on the river Segura.
Orlando, Florida
Orlando, Florida: county seat of Orange County, incorporated 1875, population about 334,000 in 2025, anchor of the 2.96-million Orlando-Kissimmee-Sanford metro and a global theme-park and tourism hub.
Orléans
Orléans, capital of France's Centre-Val de Loire region on the Loire river, 120 km from Paris; about 116,000 inhabitants. Known for the 1429 siege relieved by Joan of Arc and the UNESCO Loire Valley.
Ormoc
Ormoc, an independent component city on western Leyte, Philippines; chartered 1947 (RA 179), 238,545 people (2024), 85 barangays, Queen Pineapple and Piña Festival, site of the deadly 1991 Tropical Storm Uring flash flood.
Ormond Beach, Florida
Ormond Beach is a Volusia County, Florida city just north of Daytona Beach, incorporated April 22, 1880 as Ormond. Known for the 1888 Ormond Hotel, Rockefeller's Casements, and beach auto racing.
Oroville, California
Oroville, formerly Ophir City, is the county seat of Butte County, California, on the Feather River, best known for Oroville Dam, the tallest dam in the country.
Orsk
Orsk (Орск) is a city of about 220,000 people in Orenburg Oblast, Russia, at the mouth of the Or River, flooded in April 2024 after a dam burst.