Geography

Obersimmental District, Canton of Bern Obersimmental District Obersimmental is a mountainous district in the Simmental valley of the canton of Bern, Switzerland. It covers about 334 km² and comprises four municipalities, known for alpine past…

Obersimmental-Saanen (administrative district, canton of Bern) Obersimmental-Saanen (administrative district) Administrative district in the canton of Bern, Switzerland: a mountainous region of the Bernese Oberland covering 575 km² with seven municipalities and an economy shaped by tourism…

Oberspreewald-Lausitz Oberspreewald-Lausitz is a rural district in southern Brandenburg, Germany, noted for its Spreewald wetlands, Lusatian landscape shaped by lignite mining and a mixed German–Sorbian…

Oberstrass: Quarter of Zürich’s District 6 Oberstrass Oberstrass is a residential quarter in Zürich’s District 6. Formerly an independent municipality until 1893, it is known for mixed housing, local amenities, and its place alongside…

Oberwald — Alpine village in Goms, Valais, Switzerland Oberwald Oberwald is a high‑Alpine village and former municipality in the Goms district of Valais, Switzerland. Known for mountain passes, rail links and access to hiking and winter sports,…

Obock Region (Djibouti) Obock Region Obock Region is a sparsely populated, coastal administrative region in northern Djibouti with strategic Red Sea and Gulf of Aden frontage, desert landscapes, salt flats, and a larg…

Obwalden: central Swiss canton centered on Sarnen Obwalden Obwalden is a small, German-speaking canton in central Switzerland. Rural and mountainous, it includes lakes such as Sarnen and Lungern and forms the historic region of Unterwalden…

Očauš: a mountain of central Bosnia Očauš Očauš is a forested mountain in central Bosnia and Herzegovina, rising to 1,402 m at Mihailovac. It lies between the Vrbanja and Ukrina river basins and supports villages, pastures…

Occitanie — Region of France and the Occitania cultural area Occitanie Occitanie is a large administrative region in southern France formed in 2016 by merging Languedoc-Roussillon and Midi-Pyrénées; it also names the core of the wider historical Occit…

Occupied territory (military occupation) Occupied territory Land or territory placed under the authority of foreign armed forces without transfer of sovereignty; governed by rules of international humanitarian law and often subject to polit…

Ocean County, New Jersey Coastal county in New Jersey containing much of the Jersey Shore. County seat: Toms River. Population ~576,565. Known for beaches, barrier islands, tourism, suburban communities an…

Oceania: geography, regions, biogeography and political definitions Oceania Overview of Oceania, its variable boundaries, major subregions (Australasia, Melanesia, Micronesia, Polynesia), biogeographic concepts, and how different organizations define the r…

Odenwald: low mountain range in Hesse, Bavaria and Baden-Württemberg Odenwald The Odenwald is a forested low mountain range in southwestern Germany spanning Hesse, northern Bavaria and northern Baden-Württemberg, noted for rounded peaks, sandstone geology, m…

Odenwaldkreis Odenwaldkreis is a rural district in southern Hesse, Germany, covering part of the Odenwald uplands. It comprises towns and villages around Erbach and is known for forests, hiking,…

Oder (Odra) — Central European river Oder The Oder (Polish Odra) is a major Central European river rising in the Czech Republic, flowing through Poland and forming part of the Poland–Germany border before reaching the Balt…

Oder–Neisse line Oder-Neisse line Post–World War II frontier between Germany and Poland largely following the Oder and Lusatian Neisse rivers; established after Allied decisions in 1945 and later confirmed by inter…

Oder-Spree (district) — Brandenburg, Germany Oder-Spree Oder-Spree is a district in eastern Brandenburg, Germany, named for the Spree and Oder rivers. It encompasses industrial towns, rural areas, waterways and lakes important for trans…

Odesa Oblast Odesa Oblast is a southwestern region of Ukraine centered on the port city of Odesa, notable for its Black Sea coast, multiethnic heritage, port economy and strategic transport lin…

Oesling (Éislek): the upland region of northern Luxembourg Oesling The Oesling (Luxembourgish: Éislek) is the forested, low-mountain region in northern Luxembourg, covering roughly one-third of the country. It is sparsely populated, part of the Ar…

Ofanto The Ofanto is a river of southern Italy (Latin: Aufidus) that rises in the Apennines and flows through Campania, Basilicata and Apulia to the Adriatic Sea.

Offenbach Rural District (Landkreis Offenbach) Offenbach (district) Offenbach Rural District (Landkreis Offenbach) is an administrative district in southern Hesse, Germany, forming part of the Darmstadt region and the Rhine‑Main metropolitan area;…

Officer Creek (Aṉangu Pitjantjatjara Yankunytjatjara Lands) Officer Creek Officer Creek is an intermittent watercourse in north‑west South Australia that flows from the Musgrave Ranges into the Great Victoria Desert and is closely tied to the Aṉangu comm…

Öfnerspitze — a rocky summit of the Allgäu Alps Öfnerspitze Öfnerspitze is a 2,576 m rocky peak in the Allgäu Alps, formed of dolomite. It is linked to the Krottenspitze by a flat rock spur, rarely visited, with no marked routes; first reco…

Ofterschwang — Alpine municipality and ski venue in Oberallgäu, Bavaria Ofterschwang Ofterschwang is an Alpine municipality in Oberallgäu, Bavaria, known as a winter-sports center that hosts Alpine Ski World Cup events and received the ADAC Tourism Prize in 2010.

Ogeu-les-Bains — commune in Pyrénées-Atlantiques, southwestern France Ogeu-les-Bains Ogeu-les-Bains is a small commune in the Pyrénées-Atlantiques département of southwestern France, known for its spa-related name, rural setting at the Pyrenean foothills, and local…

Oghuz District (Oğuz) — district of Azerbaijan Oghuz District Administrative district in northwestern Azerbaijan centered on the town of Oghuz; characterized by mountainous terrain, mixed agriculture, forested landscapes, and cultural ties to…

Oglala Lakota County, South Dakota County in southwestern South Dakota, home to the Pine Ridge Reservation; renamed from Shannon County in 2015 and unique for lacking its own county seat.

Ogooué-Ivindo Province (Gabon) Ogooué-Ivindo Province Ogooué-Ivindo is a largely forested, sparsely populated province in northeastern Gabon, centered on the rivers Ogooué and Ivindo and known for its rainforests, waterfalls and prote…

Ogre, Latvia: town at the confluence of rivers Ogre, Latvia Ogre is a Latvian town east of Riga, known for its riverside setting where the Ogre and Daugava meet, municipal role, 19th-century growth with the railway, parks and local cultural…

Ogun River (Nigeria) Ogun River The Ogun River rises in Oyo State and flows through Ogun into Lagos State, emptying into Lagos Lagoon. It supports local livelihoods, recreation and ecosystems but faces pollution…

Ohangwena Region of Namibia Ohangwena Region Overview of Ohangwena Region in northern Namibia: geography, administration, history, economy, culture and development challenges, with capital at Eenhana and a border with Angola.

Ohio River: Geography, history, and role in American inland navigation Ohio River Major tributary of the Mississippi River running 981 miles from Pittsburgh; forms state borders, supports navigation and industry, and has important ecological and historical signi…

Okaloosa County, Florida County in the Florida Panhandle created in 1915. Contains Crestview (county seat) and coastal communities; economy driven by military installations, tourism and coastal commerce.

Okanagan Valley: geography, culture, economy and notable features Okanagan The Okanagan is a lake-and-valley region in British Columbia, Canada, known for its semi-arid climate, fruit orchards and wine industry, centred on Kelowna and extending into Washi…

Okanagan Lake Large, deep lake in British Columbia's Okanagan Valley known for its length, depth, recreation, towns on its shores, local ecology and the Ogopogo legend.

Okara District (Pakistan) Okara District Okara District is an administrative region in Punjab province, Pakistan, centered on the city of Okara. It is an agricultural district known for irrigated plains, canal colonies, a…

Okayama Prefecture: geography, history, culture and attractions Okayama Prefecture Okayama Prefecture, on Honshū in the Chūgoku region, is known for its mild climate, historic sites such as Korakuen and Okayama Castle, traditional crafts like Bizen ware, and its…

Okefenokee Swamp — a blackwater peatland on the Georgia–Florida border Okefenokee Swamp A large peat-filled blackwater wetland spanning Georgia and Florida, the Okefenokee Swamp is a National Wildlife Refuge and National Natural Landmark with distinctive ecology, geol…

Okinawa Prefecture Okinawa Prefecture is a subtropical island prefecture of Japan, centered on Okinawa Island with a distinct Ryukyuan history, unique culture, coral ecosystems, tourism and a signifi…

Oklahoma: geography, history, economy, and culture Oklahoma Concise encyclopedia overview of Oklahoma: its geography, history, economy, people, and notable features, with quick facts and further references.

Oklahoma County, Oklahoma — overview, history, and key facts Oklahoma County, Oklahoma Central Oklahoma county whose seat is Oklahoma City; covers government, geography, history, economy, transportation, and notable places.

Oklahoma Panhandle A narrow western extension of Oklahoma composed of three counties; covers its geography, history, economy, and notable distinctions.

Öland — Swedish island in the Baltic Sea Öland Öland is Sweden's second-largest island, long and narrow off the east coast. Known for its limestone plain, cultural landscape, wildlife and summer tourism, it is linked to the mai…

Öland County (1819–1826) — former Swedish county Öland County Short-lived administrative county on the island of Öland (Ölands län), seat at Borgholm; established 1819 and reunited with Kalmar County in 1826. Remembered in regional histories…

Olduvai Gorge: Key site for early human history in East Africa Olduvai Gorge Olduvai Gorge is a steep ravine in the eastern Serengeti of northern Tanzania, renowned for hominin fossils, stone tools, layered volcanic deposits and landmark archaeological rese…

Olia Chain (The Olias) — mountain range in southwest Northern Territory Olia chain A concise overview of the Olia Chain: location, landscape, geology, cultural significance, notable peaks and access in the remote southwest of Australia’s Northern Territory.

Olmsted County, Minnesota — Overview and History Olmsted County, Minnesota County in southeastern Minnesota containing Rochester; founded 1855 and named for David Olmsted. Known for healthcare, steady growth, and a mix of urban and agricultural communitie…

Olomouc Region — geography, history, economy and attractions Olomouc Region Overview of the Olomouc Region (Olomoucký kraj) in the Czech Republic: geography, major towns, cultural heritage, economy and recreational highlights including the Jeseníky mountai…