1.
Prime meridian
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A prime meridian is a meridian in a geographical coordinate system at which longitude is defined to be 0°. Together, a meridian and its antimeridian form a great circle. This great circle divides the sphere, e. g. the Earth, if one uses directions of East and West from a defined prime meridian, then they can be called Eastern Hemisphere and Western Hemisphere. The most widely used modern meridian is the IERS Reference Meridian and it is derived but deviates slightly from the Greenwich Meridian, which was selected as an international standard in 1884. The notion of longitude was developed by the Greek Eratosthenes in Alexandria, and Hipparchus in Rhodes, but it was Ptolemy who first used a consistent meridian for a world map in his Geographia. The main point is to be comfortably west of the tip of Africa as negative numbers were not yet in use. His prime meridian corresponds to 18°40 west of Winchester today, at that time the chief method of determining longitude was by using the reported times of lunar eclipses in different countries. Ptolemys Geographia was first printed with maps at Bologna in 1477, but there was still a hope that a natural basis for a prime meridian existed. The Tordesillas line was settled at 370 leagues west of Cape Verde. This is shown in Diogo Ribeiros 1529 map, in 1541, Mercator produced his famous 41 cm terrestrial globe and drew his prime meridian precisely through Fuertaventura in the Canaries. His later maps used the Azores, following the magnetic hypothesis, but by the time that Ortelius produced the first modern atlas in 1570, other islands such as Cape Verde were coming into use. In his atlas longitudes were counted from 0° to 360°, not 180°W to 180°E as is usual today and this practice was followed by navigators well into the 18th century. In 1634, Cardinal Richelieu used the westernmost island of the Canaries, Ferro, 19°55 west of Paris, the geographer Delisle decided to round this off to 20°, so that it simply became the meridian of Paris disguised. In the early 18th century the battle was on to improve the determination of longitude at sea, between 1765 and 1811, Nevil Maskelyne published 49 issues of the Nautical Almanac based on the meridian of the Royal Observatory, Greenwich. Maskelynes tables not only made the lunar method practicable, they made the Greenwich meridian the universal reference point. In 1884, at the International Meridian Conference in Washington, D. C.22 countries voted to adopt the Greenwich meridian as the meridian of the world. The French argued for a line, mentioning the Azores and the Bering Strait. In October 1884 the Greenwich Meridian was selected by delegates to the International Meridian Conference held in Washington, united States to be the common zero of longitude and standard of time reckoning throughout the world
2.
North America
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North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be considered a subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. North America covers an area of about 24,709,000 square kilometers, about 16. 5% of the land area. North America is the third largest continent by area, following Asia and Africa, and the fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7. 5% of the worlds population, North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge. The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago, the Classic stage spans roughly the 6th to 13th centuries. The Pre-Columbian era ended with the migrations and the arrival of European settlers during the Age of Discovery. Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists, indigenous peoples, African slaves and their descendants, European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south. Because of the history of colonialism, most North Americans speak English, Spanish or French, the Americas are usually accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass previously unknown by Europeans. In 1507, Waldseemüller produced a map, in which he placed the word America on the continent of South America. He explained the rationale for the name in the accompanying book Cosmographiae Introductio, for Waldseemüller, no one should object to the naming of the land after its discoverer. He used the Latinized version of Vespuccis name, but in its feminine form America, following the examples of Europa, Asia and Africa. Later, other mapmakers extended the name America to the continent, In 1538. Some argue that the convention is to use the surname for naming discoveries except in the case of royalty, a minutely explored belief that has been advanced is that America was named for a Spanish sailor bearing the ancient Visigothic name of Amairick. Another is that the name is rooted in a Native American language, the term North America maintains various definitions in accordance with location and context. In Canadian English, North America may be used to refer to the United States, alternatively, usage sometimes includes Greenland and Mexico, as well as offshore islands
3.
Pacific Ocean
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The Pacific Ocean is the largest and deepest of the Earths oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean in the south and is bounded by Asia and Australia in the west, the Mariana Trench in the western North Pacific is the deepest point in the world, reaching a depth of 10,911 metres. Both the center of the Water Hemisphere and the Western Hemisphere are in the Pacific Ocean, the oceans current name was coined by Portuguese explorer Ferdinand Magellan during the Spanish circumnavigation of the world in 1521, as he encountered favourable winds on reaching the ocean. He called it Mar Pacífico, which in both Portuguese and Spanish means peaceful sea, important human migrations occurred in the Pacific in prehistoric times. Long-distance trade developed all along the coast from Mozambique to Japan, trade, and therefore knowledge, extended to the Indonesian islands but apparently not Australia. By at least 878 when there was a significant Islamic settlement in Canton much of trade was controlled by Arabs or Muslims. In 219 BC Xu Fu sailed out into the Pacific searching for the elixir of immortality, from 1404 to 1433 Zheng He led expeditions into the Indian Ocean. The east side of the ocean was discovered by Spanish explorer Vasco Núñez de Balboa in 1513 after his expedition crossed the Isthmus of Panama and he named it Mar del Sur because the ocean was to the south of the coast of the isthmus where he first observed the Pacific. Later, Portuguese explorer Ferdinand Magellan sailed the Pacific East to West on a Castilian expedition of world circumnavigation starting in 1519, Magellan called the ocean Pacífico because, after sailing through the stormy seas off Cape Horn, the expedition found calm waters. The ocean was often called the Sea of Magellan in his honor until the eighteenth century, sailing around and east of the Moluccas, between 1525 and 1527, Portuguese expeditions discovered the Caroline Islands, the Aru Islands, and Papua New Guinea. In 1542–43 the Portuguese also reached Japan, in 1564, five Spanish ships consisting of 379 explorers crossed the ocean from Mexico led by Miguel López de Legazpi and sailed to the Philippines and Mariana Islands. The Manila galleons operated for two and a half centuries linking Manila and Acapulco, in one of the longest trade routes in history, Spanish expeditions also discovered Tuvalu, the Marquesas, the Cook Islands, the Solomon Islands, and the Admiralty Islands in the South Pacific. In the 16th and 17th century Spain considered the Pacific Ocean a Mare clausum—a sea closed to other naval powers, as the only known entrance from the Atlantic the Strait of Magellan was at times patrolled by fleets sent to prevent entrance of non-Spanish ships. On the western end of the Pacific Ocean the Dutch threatened the Spanish Philippines, Spain also sent expeditions to the Pacific Northwest reaching Vancouver Island in southern Canada, and Alaska. The French explored and settled Polynesia, and the British made three voyages with James Cook to the South Pacific and Australia, Hawaii, and the North American Pacific Northwest, one of the earliest voyages of scientific exploration was organized by Spain in the Malaspina Expedition of 1789–1794. It sailed vast areas of the Pacific, from Cape Horn to Alaska, Guam and the Philippines, New Zealand, Australia, and the South Pacific. Growing imperialism during the 19th century resulted in the occupation of much of Oceania by other European powers, and later, Japan, in Oceania, France got a leading position as imperial power after making Tahiti and New Caledonia protectorates in 1842 and 1853 respectively. After navy visits to Easter Island in 1875 and 1887, Chilean navy officer Policarpo Toro managed to negotiate an incorporation of the island into Chile with native Rapanui in 1888, by occupying Easter Island, Chile joined the imperial nations
4.
Southern Ocean
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As such, it is regarded as the fourth-largest of the five principal oceanic divisions, smaller than the Pacific, Atlantic, and Indian Oceans but larger than the Arctic Ocean. This ocean zone is cold, northward flowing waters from the Antarctic mix with warmer subantarctic waters. By way of his voyages in the 1770s, Captain James Cook proved that waters encompassed the southern latitudes of the globe. Since then, geographers have disagreed on the Southern Oceans northern boundary or even existence, considering the part of the Pacific, Atlantic. Others regard the seasonally-fluctuating Antarctic Convergence as the natural boundary, Borders and names for oceans and seas were internationally agreed when the International Hydrographic Bureau, the precusor to the IHO, convened the First International Conference on 24 July 1919. The IHO then published these in its Limits of Oceans and Seas, Australian authorities regard the Southern Ocean as lying immediately south of Australia. Map publishers using the term Southern Ocean on their maps include Hema Maps, Southern Ocean is an obsolete name for the Pacific Ocean or South Pacific, coined by Vasco Núñez de Balboa, the first European to discover it, who approached it from the north. The South Seas is an archaic synonym. A1745 British Act of Parliament established a prize for discovering a Northwest Passage to the Western and Southern Ocean of America, authors using Southern Ocean to name the waters encircling the unknown southern polar regions used varying limits. James Cooks account of his second voyage implies New Caledonia borders it, peacocks 1795 Geographical Dictionary said it lay to the southward of America and Africa, John Payne in 1796 used 40 degrees as the northern limit, the 1827 Edinburgh Gazetteer used 50 degrees. The United Kingdoms South Australia Act 1834 described the waters forming the southern limit of the new colony of South Australia as the Southern Ocean. The Colony of Victorias Legislative Council Act of 1881 delimited part of the division of Bairnsdale as along the New South Wales boundary to the Southern ocean. The limit then followed the west coast of Tasmania southwards to the South East Cape and then went eastwards to Broughton Island, New Zealand, the northern limits of the Southern Ocean were moved southwards in the IHOs 1937 second edition of the Limits of Oceans and Seas. From this edition, much of the northern limit ceased to abut land masses. As is discussed in detail below, prior to the 2002 edition the limits of oceans explicitly excluded the seas lying within each of them. The Great Australian Bight was unnamed in the 1928 edition, and it therefore encompassed former Southern Ocean waters but was technically not inside any of the three adjacent oceans by 1937. To perform direct comparisons of current and former limits of oceans it is necessary to consider, or at least be aware of, the limits of the Atlantic, Pacific and Indian Oceans have therefore been extended South to the Antarctic Continent. The IHO readdressed the question of the Southern Ocean in a survey in 2000, of its 68 member nations,28 responded, and all responding members except Argentina agreed to redefine the ocean, reflecting the importance placed by oceanographers on ocean currents
5.
South Pole
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The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earths axis of rotation intersects its surface. It is the southernmost point on the surface of the Earth, situated on the continent of Antarctica, it is the site of the United States Amundsen–Scott South Pole Station, which was established in 1956 and has been permanently staffed since that year. The Geographic South Pole should not be confused with the South Magnetic Pole, the South Pole is at the center of the Southern Hemisphere. For most purposes, the Geographic South Pole is defined as the point of the two points where the Earths axis of rotation intersects its surface. However, the Earths axis of rotation is actually subject to very small wobbles, the geographic coordinates of the South Pole are usually given simply as 90°S, since its longitude is geometrically undefined and irrelevant. When a longitude is desired, it may be given as 0°, at the South Pole, all directions face north. For this reason, directions at the Pole are given relative to grid north, along tight latitude circles, clockwise is east, and counterclockwise is west, opposite to the North Pole. The Geographic South Pole is located on the continent of Antarctica. It sits atop a featureless, barren, windswept and icy plateau at an altitude of 2,835 metres above sea level, and is located about 1,300 km from the nearest open sea at Bay of Whales. The ice is estimated to be about 2,700 metres thick at the Pole, the polar ice sheet is moving at a rate of roughly 10 metres per year in a direction between 37° and 40° west of grid north, down towards the Weddell Sea. Therefore, the position of the station and other artificial features relative to the geographic pole gradually shift over time. The Geographic South Pole is marked by a stake in the ice alongside a small sign, these are repositioned each year in a ceremony on New Years Day to compensate for the movement of the ice. The sign records the respective dates that Roald Amundsen and Robert F. Scott reached the Pole, followed by a quotation from each man. A new marker stake is designed and fabricated each year by staff at the site, the Ceremonial South Pole is an area set aside for photo opportunities at the South Pole Station. It is located around 180 metres from the Geographic South Pole, Amundsens Tent, The tent was erected by the Norwegian expedition led by Roald Amundsen on its arrival on 14 December 1911. It is currently buried beneath the snow and ice in the vicinity of the Pole and it has been designated a Historic Site or Monument, following a proposal by Norway to the Antarctic Treaty Consultative Meeting. In 1820, several expeditions claimed to have been the first to have sighted Antarctica, with the very first being the Russian expedition led by Faddey Bellingshausen and Mikhail Lazarev. The first landing was probably just over a year later when American Captain John Davis, the basic geography of the Antarctic coastline was not understood until the mid-to-late 19th century
6.
Nunavut
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Nunavut is the newest, largest, and northernmost territory of Canada. The creation of Nunavut resulted in the first major change to Canadas political map since the incorporation of the province of Newfoundland, Nunavut comprises a major portion of Northern Canada, and most of the Canadian Arctic Archipelago. Its vast territory makes it the fifth-largest country subdivision in the world, the capital Iqaluit, on Baffin Island in the east, was chosen by the 1995 capital plebiscite. Other major communities include the regional centres of Rankin Inlet and Cambridge Bay and it is Canadas only geo-political region that is not connected to the rest of North America by highway. Nunavut is the largest in area and the second least populous of Canadas provinces and territories. One of the worlds most remote, sparsely settled regions, it has a population of 35,944, mostly Inuit, spread over an area of just over 1,750,000 km2, Nunavut is also home to the worlds northernmost permanently inhabited place, Alert. A weather station farther down Ellesmere Island, Eureka, has the lowest average temperature of any Canadian weather station. Nunavut means our land in Inuktitut, Nunavut covers 1,877,787 km2 of land and 160,935 km2 of water in Northern Canada. This makes it the fifth largest subnational entity in the world, if Nunavut were a country, it would rank 15th in area. It also shares borders with Greenland and the provinces of Quebec, Ontario. Nunavuts highest point is Barbeau Peak on Ellesmere Island, the population density is 0.019 persons/km2, one of the lowest in the world. By comparison, Greenland has approximately the area and nearly twice the population. Nunavut experiences a climate in most regions, owing to its high latitude. In more southerly continental areas very cold climates can be found. The region now known as Nunavut has supported an indigenous population for approximately 4,000 years. Most historians identify the coast of Baffin Island with the Helluland described in Norse sagas, the materials were collected in five seasons of excavation at Cape Tanfield. Scholars determined that these provide evidence of European traders and possibly settlers on Baffin Island and they seem to indicate prolonged contact, possibly up to 1450. So you have to consider the possibility that as remote as it may seem, the ore turned out to be worthless, but Frobisher made the first recorded European contact with the Inuit
7.
Manitoba
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Manitoba is a province at the longitudinal centre of Canada. It is one of the three provinces and Canadas fifth-most populous province with its estimated 1.3 million people. Manitoba covers 649,950 square kilometres with a varied landscape. Aboriginal peoples have inhabited what is now Manitoba for thousands of years, in the late 17th century, fur traders arrived in the area when it was part of Ruperts Land and owned by the Hudsons Bay Company. In 1869, negotiations for the creation of the province of Manitoba led to an uprising of the Métis people against the Government of Canada. The rebellions resolution led to the Parliament of Canada passing the Manitoba Act in 1870 that created the province, Manitobas capital and largest city, Winnipeg, is Canadas eighth-largest census metropolitan area. Winnipeg is the seat of government, home to the Legislative Assembly of Manitoba, four of the provinces five universities and all four of its professional sports teams are in Winnipeg. The name Manitoba is believed to be derived from the Cree, the name derives from Cree manitou-wapow or Ojibwa manidoobaa, both meaning straits of Manitou, the Great Spirit, a place referring to what are now called The Narrows in the centre of Lake Manitoba. It may also be from the Assiniboine for Lake of the Prairie, the lake was known to French explorers as Lac des Prairies. Thomas Spence chose the name to refer to a new republic he proposed for the south of the lake. Métis leader Louis Riel also chose the name, and it was accepted in Ottawa under the Manitoba Act of 1870 and it adjoins Hudson Bay to the northeast, and is the only prairie province to have a saltwater coastline. The Port of Churchill is Canadas only Arctic deep-water port and the shortest shipping route between North America and Asia, Lake Winnipeg is the tenth-largest freshwater lake in the world. Hudson Bay is the worlds second-largest bay, Manitoba is at the heart of the giant Hudson Bay watershed, once known as Ruperts Land. It was a area of the Hudsons Bay Company, with many rivers. The province has a saltwater coastline bordering Hudson Bay and more than 110,000 lakes, Manitobas major lakes are Lake Manitoba, Lake Winnipegosis, and Lake Winnipeg, the tenth-largest freshwater lake in the world. Some traditional Native lands and boreal forest on Lake Winnipegs east side are a proposed UNESCO World Heritage Site. Manitoba is at the centre of the Hudson Bay drainage basin, with a volume of the water draining into Lake Winnipeg. This basins rivers reach far west to the mountains, far south into the United States, major watercourses include the Red, Assiniboine, Nelson, Winnipeg, Hayes, Whiteshell and Churchill rivers
8.
United States
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Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
9.
North Dakota
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North Dakota is the 39th state of the United States, having been admitted to the union on November 2,1889. The state capital is Bismarck, and the largest city is Fargo, North Dakota is the 19th most extensive but the 4th least populous and the 4th least densely populated of the 50 United States. The development has driven strong job and population growth, and low unemployment, North Dakota is located in the U. S. region known as the Great Plains. The state shares the Red River of the North with Minnesota on the east, South Dakota is to the south, Montana is to the west, and the Canadian provinces of Saskatchewan and Manitoba are to the north. North Dakota is situated near the middle of North America with a marker in Rugby. With an area of 70,762 square miles, North Dakota is the 19th largest state, the western half of the state consists of the hilly Great Plains as well as the northern part of the Badlands, which are to the west of the Missouri River. The states high point, White Butte at 3,506 feet, the region is abundant in fossil fuels including natural gas, crude oil and lignite coal. The Missouri River forms Lake Sakakawea, the third largest man-made lake in the United States, the central region of the state is divided into the Drift Prairie and the Missouri Plateau. The eastern part of the consists of the flat Red River Valley. Its fertile soil, drained by the meandering Red River flowing northward into Lake Winnipeg, Devils Lake, the largest natural lake in the state, is also found in the east. Eastern North Dakota is overall flat, however, there are significant hills, most of the state is covered in grassland, crops cover most of eastern North Dakota but become increasingly sparse in the center and farther west. This diverse terrain supports nearly 2,000 species of plants, the state of North Dakota is home to the geographical center of North America located near Rugby, North Dakota North Dakota has a continental climate with hot summers and cold winters. The temperature differences are rather extreme because of its far inland position and being in the center of the Northern Hemisphere, with equal distances to the North Pole. As such, summers are almost subtropical in nature, but winters are cold enough to plant hardiness is very low. Native American peoples lived in what is now North Dakota for thousands of years before the coming of Europeans and their tribes included the Mandan people, the Dakota people and the Yanktonai, the latter two from the Lakota peoples. The first European to reach the area was the French-Canadian trader Pierre Gaultier, sieur de La Vérendrye, in 1762 the region became part of Spanish Louisiana until 1802. Dakota Territory was settled sparsely by European Americans until the late 19th century, with the advantage of grants of land, they vigorously marketed their properties, extolling the region as ideal for agriculture. An omnibus bill for statehood for North Dakota, South Dakota, Montana and his successor, Benjamin Harrison, signed the proclamations formally admitting North Dakota and South Dakota to the Union on November 2,1889
10.
South Dakota
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South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux Native American tribes, South Dakota is the 17th most expansive, but the 5th least populous and the 5th least densely populated of the 50 United States. Once the southern portion of the Dakota Territory, South Dakota became a state on November 2,1889, Pierre is the state capital and Sioux Falls, with a population of about 171,000, is South Dakotas largest city. South Dakota is bordered by the states of North Dakota, Minnesota, Iowa, Nebraska, Wyoming, the state is bisected by the Missouri River, dividing South Dakota into two geographically and socially distinct halves, known to residents as East River and West River. Eastern South Dakota is home to most of the states population, West of the Missouri, ranching is the predominant agricultural activity, and the economy is more dependent on tourism and defense spending. Most of the Native American reservations are located in West River, the Black Hills, a group of low pine-covered mountains sacred to the Sioux, are located in the southwest part of the state. Mount Rushmore, a major tourist destination, is located there, South Dakota experiences a temperate continental climate, with four distinct seasons and precipitation ranging from moderate in the east to semi-arid in the west. The ecology of the state features species typical of a North American grassland biome, humans have inhabited the area for several millennia, with the Sioux becoming dominant by the early 19th century. In the late 19th century, European-American settlement intensified after a rush in the Black Hills. Encroaching miners and settlers triggered a number of Indian wars, ending with the Wounded Knee Massacre in 1890, historically dominated by an agricultural economy and a rural lifestyle, South Dakota has recently sought to diversify its economy in areas to attract and retain residents. South Dakotas history and rural character still strongly influence the culture of the state, South Dakota is situated in the north-central United States, and is considered a part of the Midwest by the U. S. Census Bureau, it is also part of the Great Plains region. The culture, economy, and geography of western South Dakota have more in common with the West than the Midwest, South Dakota has a total area of 77,116 square miles, making the state the 17th largest in the Union. Black Elk Peak, formerly named Harney Peak, with an elevation of 7,242 ft, is the states highest point, while the shoreline of Big Stone Lake is the lowest, with an elevation of 966 ft. South Dakota is bordered to the north by North Dakota, to the south by Nebraska, to the east by Iowa and Minnesota, the geographical center of the U. S. is 17 miles west of Castle Rock in Butte County. The North American continental pole of inaccessibility is located between Allen and Kyle,1,024 mi from the nearest coastline, the Missouri River is the largest and longest river in the state. Other major South Dakota rivers include the Cheyenne, James, Big Sioux, Eastern South Dakota has many natural lakes, mostly created by periods of glaciation. Additionally, dams on the Missouri River create four large reservoirs, Lake Oahe, Lake Sharpe, Lake Francis Case, South Dakota can generally be divided into three regions, eastern South Dakota, western South Dakota, and the Black Hills. The Missouri River serves as a boundary in terms of geographic, social, at times the Black Hills are combined with the rest of western South Dakota, and people often refer to the resulting two regions divided by the Missouri River as West River and East River
