Geography

Olpe (district) Olpe is a rural district in the Sauerland region of North Rhine-Westphalia, Germany. It features hilly forests, reservoirs, small towns and local industry, with a history rooted in…

Olt River Olt (river) Major Romanian river rising in the Carpathians and flowing south through Transylvania and Wallachia; historically known as Alutus/Aluta and important for valleys, hydroelectricity…

Olt County (Romania) Olt County Olt County is a Romanian administrative region centered on the city of Slatina, spanning the Olt River valley and parts of the historical regions Oltenia and Muntenia.

Olten District (Canton of Solothurn, Switzerland) Olten District Olten District is an administrative district in the canton of Solothurn, Switzerland, centered on the city of Olten. It is known for its transport hub, mixed economy, and riverside…

Oltenia — historical region of southwestern Romania Oltenia Oltenia is a historical province in southwestern Romania, part of Wallachia. Bounded by the Olt and Danube rivers and the Southern Carpathians, it comprises the counties of Dolj, G…

Oltingue, Haut-Rhin (France) Oltingue Oltingue is a small commune in the Haut-Rhin department in eastern France. Situated in the historical region of Alsace near the Swiss border, it is a rural village with agricultura…

Olympic Mountains (Washington State) Olympic Mountains A rugged, largely roadless range on Washington's Olympic Peninsula: geology, climates from temperate rainforests to alpine peaks, human history, protected lands, and recreational s…

Mount Olympus: geography, mythology, ecology, and human use Olympus Mount Olympus (Greek Όλυμπος) is Greece's highest mountain, famed as the mythical home of the Greek gods and notable for its geology, biodiversity, protected status, and mountainee…

Omaheke Region (Namibia): geography, people, economy and administration Omaheke Region Omaheke is an eastern Namibian region centered on Gobabis. Semi-arid Kalahari plains, cattle ranching, sparse population, seven constituencies, and governance under Governor Pijoo…

Oman: overview, geography, history, and culture of the Sultanate Oman Oman is a sovereign state on the southeastern Arabian Peninsula. This article summarizes its geography, government, history, economy, society, and cultural highlights, with links t…

Ombella-M'Poko (prefecture of the Central African Republic) Ombella-M'Poko Ombella-M'Poko is a prefecture of the Central African Republic with capital at Bimbo. Located near the national capital region, it contains river valleys, agricultural areas and ke…

Ōmi Province (Ōmi no kuni) Ōmi Province Historic Japanese province centered on Lake Biwa, corresponding to modern Shiga Prefecture. Known as Gōshū, with Ōtsu as its ancient capital and a long cultural and commercial hist…

Omusati Region (Namibia) Omusati Region Omusati is a northern Namibian region centered on Outapi; noted for Ruacana Falls, the Omugulugwombashe heritage site, subsistence agriculture, Ovambo culture and twelve constituen…

Onon River (Mongolia and Russia) Onon (river) Transboundary river rising in the Khentii Mountains; about 818 km long, joins the Ingoda to form the Shilka and is the headwater of the Amur river system. Important for ecology, hi…

Ontario (province of Canada) Ontario Comprehensive overview of Ontario: geography, major cities (Toronto, Ottawa), history, government, economy, Indigenous peoples, natural environment, symbols, transportation and fur…

Ontario Highway 144 Ontario Highway 144 is a 271.7 km provincial route linking Sudbury with Highway 101 near Timmins across largely remote areas of Northern Ontario, serving resource industries and lo…

Ontario Highway 33 (King's Highway 33) — Loyalist Parkway Ontario Highway 33 Provincial King's Highway 33 in Ontario: a 61 km scenic route from Prince Edward County across the Glenora Ferry to Kingston, designated the Loyalist Parkway to honor United Empire…

Ontario Lacus — a hydrocarbon lake on Titan Ontario Lacus Ontario Lacus is a large methane–ethane lake near Titan's south pole, identified by Cassini. It resembles Earth's Lake Ontario in size and shape and illustrates Titan's active orga…

Onyx River — Antarctica’s longest seasonal meltwater stream Onyx River Seasonal meltwater river in the McMurdo Dry Valleys of Antarctica. Flows westward through Wright Valley into Lake Vanda; studied for hydrology, ecology and climate change.

Opole Voivodeship A concise overview of Opole Voivodeship (Opolskie): location in southern Poland, historical ties to Upper Silesia, capital Opole, administration, economy, culture and notable featu…

Orakzai District Orakzai District, formerly Orakzai Agency in Pakistan's tribal belt, is a mountainous Pashtun-inhabited district with several tehsils, notable tribal history, and administrative ch…

Oran Province (Wilaya of Oran) — Overview, geography, history and economy Oran Province Oran Province (Wilaya of Oran) is a coastal province in northwestern Algeria with the city of Oran as its capital. It is an economic and cultural hub with a reported population of…

Orange County Overview of the eight U.S. counties named Orange County, their origins, key characteristics, and how the name is used in geography and culture.

Orange County, Florida Central Florida county anchored by Orlando. A tourism and convention hub historically linked to citrus, now home to major theme parks, Orlando International Airport, and a diverse,…

Orange County, Texas Orange County is a coastal county in southeastern Texas on the Sabine River and Sabine Lake. The county seat is Orange; the area has industrial ports, shipbuilding heritage, and Gu…

Orange River (Oranje / Senqu) Orange River A major river of southern Africa, the Orange River (Oranje or Senqu) flows from the Lesotho highlands to the Atlantic, forming borders, supplying water for irrigation and hydropowe…

Orangeburg County, South Carolina County in the central Midlands of South Carolina with county seat Orangeburg; created in 1769. 2010 population 92,501; part of the Columbia–Orangeburg–Newberry combined statistical…

Ordnance Survey National Grid A coordinate and mapping system used across Great Britain by Ordnance Survey; divides the country into lettered 100 km squares and numeric eastings/northings for metre-level precis…

Ore Mountains (Erzgebirge / Krušné hory): geography, mining and cultural heritage Ore Mountains A concise overview of the Ore Mountains on the Germany–Czech border: geography, mining history, traditional crafts, Christmas folk art and modern tourism.

Oregon Territory (U.S. organized territory, 1848–1859) Oregon Territory Former organized U.S. territory created from the southern Oregon Country in 1848; later subdivided into states and territories including Oregon and Washington and reconfigured thro…

Öregrund — coastal town in Uppsala County, Sweden Öregrund Öregrund is a small coastal town in Uppsala County, Sweden, known for its wooden buildings, marina and access to the archipelago; it has been part of Östhammar Municipality since 1…

Orient (term for the east) Orient Orient denotes the east; a geographic, cultural and linguistic concept from Latin oriens. Its meaning has shifted over time and appears in place names, descriptions of regions, and…

Orinoco River: Geography, Ecology and Human Uses Orinoco Explore the Orinoco River of northern South America — its 2,140 km course, 880,000 km² basin, unique ecosystems and endangered species, and its role in transport, fishing and local…

Orion, Pyrénées-Atlantiques (commune in southwestern France) Orion, Pyrénées-Atlantiques Orion is a small rural commune in the Pyrénées-Atlantiques department of southwestern France. The article summarizes its geography, history, administration, economy and cultural co…

Orne (department) — Normandy department of France Orne Orne (département 61) is a rural department in Normandy, France, centered on Alençon. Known for rolling bocage, Perche hills, forests, horse breeding and regional heritage includin…

Oromia Region, Ethiopia Oromia Oromia is Ethiopia's largest regional state by population and area, the traditional homeland of the Oromo people, surrounding the federal capital Addis Ababa (Finfinne) and notable…

Orsanco Orsanco is a small rural commune in Pyrénées-Atlantiques, southwestern France, historically part of Lower Navarre with Basque cultural ties and a predominately pastoral landscape.

Orsans (Aude) — Small commune in Occitanie, France Orsans, Aude Orsans is a small rural commune in the Aude department of Occitanie, southern France. Population 104 (2017). Article covers location, administration, economy, heritage and practica…

Ortac (islet near Alderney) Ortac Ortac is a small uninhabited islet about 5 km west of Alderney in the Channel Islands, noted for its rocky profile, modest dimensions, uncertain Norman-derived name, and occasional…

Ortenaukreis — district in Baden-Württemberg, Germany Ortenaukreis Ortenaukreis is a rural district in southwestern Germany along the Rhine, known for Black Forest scenery, vineyards, cross‑border ties with Strasbourg and a mixed economy of touris…

Oruro Department (Bolivia) Oruro Department Highland department in Bolivia centered on the mining city of Oruro; known for its high-altitude plains, mining history, indigenous cultures and the UNESCO-listed Carnival of Oruro…

Osage River (Missouri) Osage River A major tributary of the Missouri River in central Missouri, the Osage River is known for its reservoirs, hydroelectric dams, recreational lakes, and its name from the Osage Nation…

Osborne County, Kansas — overview, geography, history, and communities Osborne County, Kansas Osborne County is a small, rural county in Kansas. This article summarizes its location, population (2010 census), geography, economy, local government, and community character.

Oshana Region, Namibia: geography, economy, culture, and environment Oshana Region Overview of Namibia's Oshana Region: geography, people, economy (omahangu and cattle), floodplain ecosystems, history, governance and contemporary issues.

Oshikoto Region (Namibia) Oshikoto Region Oshikoto is an administrative region in northern Namibia, named for Lake Otjikoto. Its capital is Omuthiya; Tsumeb is a notable former capital and mining center.

Osijek-Baranja County — geography, history, economy and attractions Osijek-Baranja County Osijek-Baranja County is an eastern Croatian region centered on the city of Osijek. It combines Pannonian plains, river wetlands and multicultural heritage with agriculture, indust…

Oslofjord: geography, history, uses and notable features Oslofjord Oslofjord is a roughly 100 km inlet on Norway's southeast coast leading to Oslo. It supports shipping and ferries, contains a populated archipelago and recreational waters, and has…

Osnabrück (district) Osnabrück is a Landkreis in Lower Saxony, Germany, surrounding but administratively separate from the City of Osnabrück. The district mixes lowland agriculture, wooded hills and me…