North America

North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. North America includes all of the mainland and related offshore islands lying N of the Isthmus of Panama (which connects it with South America). The term "Anglo-America" is frequently used in reference to Canada Canada (kăn`ədə), independent nation (2001 pop. 30,007,094), 3,851,787 sq mi (9,976,128 sq km), N North America...... Click the link for more information. and the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area...... Click the link for more information. combined, while the term "Middle America" is used to describe the region including Mexico Mexico (mĕk`sĭkō), Span...... Click the link for more information. , the republics of Central America, and the Caribbean.

Geology and Geography The continent is bounded on the north by the Arctic Ocean, on the west by the Pacific Ocean and the Bering Sea, and on the east by the Atlantic Ocean and the Gulf of Mexico. Its coastline is long and irregular. With the exception of the Gulf of Mexico, Hudson Bay is by far the largest body of water indenting the continent; others include the Gulf of St. Lawrence and the Gulf of California (Sea of Cortès). There are numerous islands off the continent's coasts; Greenland and the Arctic Archipelago, the Greater and Lesser Antilles, the Alexander Archipelago, and the Aleutian Islands are the principal groups. Mt. McKinley (Denali; 20,320 ft/6,194 m), Alaska, is the highest point on the continent; the lowest point (282 ft/86 m below sea level) is in Death Valley, Calif. The Missouri-Mississippi river system (c.3,740 mi/6,020 km long) is the longest of North America. Together with the Ohio River and numerous other tributaries, it drains most of S central North America and forms the world's greatest inland waterway system. Other major rivers include the Colorado, Columbia, Delaware, Mackenzie, Nelson, Rio Grande, St. Lawrence, Susquehanna, and Yukon. Lake Superior (31,820 sq mi/82,414 sq km), the westernmost of the Great Lakes Great Lakes, group of five freshwater lakes, central North America, creating a natural border between the United States and Canada and forming the largest body of freshwater in the world, with a combined surface area of c.95,000 sq mi (246,050 sq km)...... Click the link for more information. , is the continent's largest lake. The Saint Lawrence Seaway Saint Lawrence Seaway, international waterway, 2,342 mi (3,769 km) long, consisting of a system of canals, dams, and locks in the St. Lawrence River and connecting channels between the Great Lakes; opened 1959...... Click the link for more information. , which utilizes the St. Lawrence River and the Great Lakes, enables oceangoing vessels to penetrate into the heart of North America. Physiographically, the Anglo-American section of the continent may be divided into five major regions: the Canadian Shield Canadian Shield or Laurentian Plateau (lôrĕn`chən)..... Click the link for more information. , a geologically stable area of ancient rock that occupies most of the northeastern quadrant, including Greenland; the Appalachian Mountains Great Appalachian Valley is a chain of lowlands extending S and W from the Hudson Valley; its main segments are the Lehigh, Lebanon, Cumberland, and Shenandoah valleys; the Valley of Virginia; and the Valley of East Tennessee...... Click the link for more information. , a geologically old and eroded system that extends from the Gaspé Peninsula to Alabama; the Atlantic-Gulf Coastal Plain, a belt of lowlands widening to the south that extends from S New England to Mexico; the Interior Lowlands, which extend down the middle of the continent from the Mackenzie valley to the Gulf Coastal Plain and includes the Great Plains on the west and the agriculturally productive Interior Plains on the east; and the North American Cordillera, a complex belt of geologically young mountains and associated plateaus and basins, which extend from Alaska into Mexico and include two orogenic belts—the Pacific Margin Pacific Margin, western section of the great North American Cordillera, W United States and W Canada, stretching from SW Alaska to S Calif. It is composed of a central lowland region (Central Valley, Willamette valley, Puget Sound lowlands) flanked by the Coast..... Click the link for more information. on the west and the Rocky Mountains Rocky Mountain National Park (265,723 acres/107,580 hectares) is in central Colorado. Straddling the Continental Divide in the Front Range of the Southern Rockies, the park features more than 100 peaks towering over 11,000 ft (3,353 m). The highest is Longs Peak (14,255 ft/4,345 m)...... Click the link for more information. on the east—separated by a system of intermontane plateaus and basins. The Coastal Plain and the main belts of the North American Cordillera continue south into Mexico (where the Mexican Plateau, bordered by the Sierra Madre Oriental and the Sierra Madre Occidental, is considered a continuation of the intermontane system) to join the Transverse Volcanic Range, a zone of high and active volcanic peaks S of Mexico City. During the Ice Age of the late Cenozoic era, a continental ice sheet, centered west of Hudson Bay (the floor of which is slowly rebounding after being depressed by the great weight of the ice), covered most of N North America; glaciers descended the slopes of the Rocky Mts. and those of the Pacific Margin. Extensive glacial lakes, such as Bonneville (see under Bonneville Salt Flats Lake Bonneville, whose area once covered c.19,500 sq mi (50,500 sq km). The lake expanded during the late Cenozoic era, then shrank rapidly at the end of the Pleistocene epoch. Six terraces indicate different lake levels...... Click the link for more information. ), Lahontan Lahontan, Lake (ləhŏn`tən), extinct lake of W Nev. and NE Calif...... Click the link for more information. , Agassiz Agassiz, Lake, glacial lake of the Pleistocene epoch , c.700 mi (1,130 km) long, 250 mi (400 km) wide, formed by the melting of the continental ice sheet some 10,000 years ago; covered much of present-day NW Minnesota, NE North Dakota, S Manitoba, and SW Ontario...... Click the link for more information. , and Algonquin, were formed by glacial meltwater; their remnants are still visible in the Great Basin Great Basin National Park (77,180 acres/31,258 hectares) is located in the South Snake Range of E Nevada. It has exceptional scenic and geologic attractions, including Lehman Caves and Wheeler Peak (the highest point in the park, with Nevada's only glacier and groves of bristlecone..... Click the link for more information. and along the edge of the Canadian Shield in the form of the Great Salt Lake Great Salt Lake, shallow body of saltwater, NW Utah, between the Wasatch Range on the east and the Great Salt Lake Desert on the west; largest salt lake in North America...... Click the link for more information. , the Great Lakes, and the large lakes of W central Canada.

Climate North America, extending to within 10° of latitude of both the equator and the North Pole, embraces every climatic zone, from tropical rain forest and savanna on the lowlands of Central America to areas of permanent ice cap in central Greenland. Subarctic and tundra climates prevail in N Canada and N Alaska, and desert and semiarid conditions are found in interior regions cut off by high mountains from rain-bearing westerly winds. However, a high proportion of the continent has temperate climates very favorable to settlement and agriculture.

People The first human inhabitants of North America are believed to be of Asian origin; they crossed over to Alaska from NE Asia roughly 20,000 years ago, and then moved southward through the Mackenzie River valley. European discovery and settlement of North America dates from the 10th cent., when Norsemen settled (986) in Greenland. Although evidence is fragmentary, they probably reached E Canada c.1000 at the latest. Of greater impact on the subsequent history of the continent were Christopher Columbus's exploration of the Bahamas in 1492 and later landings in the West Indies and Central America, and John Cabot's explorations of E Canada (1497), which established English claims to the continent. Spanish and French expeditions also explored much of North America. Although the population of Canada and the United States is still largely of European origin, it is growing increasingly diverse with substantial immigration from Asia, Latin America, and Africa; it is also highly urbanized (about 74% live in urban areas); much of the population is centered in large conurbations and coalescing urban belts along the southern margin of Canada and in the northeastern quadrant of the United States around the Great Lakes and along the Atlantic coast. Mexico's population, about 60% mestizo (of European and Native American descent), is increasingly urbanized (about 72%). People of European descent are a minority in most Central American and Caribbean countries, and the population outside the major cities is largely rural. The largest urban agglomerations on the continent are Mexico City, New York City, Los Angeles, and Chicago.

Resources and Economy North America's extensive agricultural lands (especially in Canada and the United States) are a result of the interrelationship of favorable climatic conditions, fertile soils, and technology. Irrigation has turned certain arid and semiarid regions into productive oases. North America produces most of the world's corn, meat, cotton, soybeans, tobacco, and wheat, along with a variety of other food and industrial raw material crops. Mineral resources are also abundant; the large variety includes coal, iron ore, bauxite, copper, natural gas, petroleum, mercury, nickel, potash, and silver. The manufacturing that provided a high standard of living for the people of Canada and the United States has significantly declined, and formerly abundant factory jobs are increasingly replaced by those in the service sector. Much of this manufacturing has moved to Mexico (especially in the border zone adjoining the United States), which offers a large and inexpensive labor force.

Bibliography See T. H. Clark and C. W. Stearn, The Geological Evolution of North America (1968); W. P. Cumming et al., The Discovery of North America (1972); R. C. West et al., Middle America: Its Lands and Peoples (3d ed. 1989); T. L. McKnight, Regional Geography of the United States and Canada (1992); S. Birdsall, Regional Landscapes of the United States and Canada (4th rev. ed. 1992); T. Flannery, The Eternal Frontier: An Ecological History of North America and Its Peoples (2001); A. Taylor, American Colonies (2001). columbia() The Columbia Electronic Encyclopedia® Copyright © 2007, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/

North America Continent, Western Hemisphere. The third-largest continent on earth, it lies mostly between the Arctic Circle and the Tropic of Cancer. It is almost completely surrounded by bodies of water, including the Pacific Ocean, the Bering Strait, the Arctic Ocean, the Atlantic Ocean, and the Caribbean Sea and Gulf of Mexico. Area: 9,361,791 sq mi (24,247,039 sq km). Population (2001 est.): 454,225,000. Shaped like an inverted triangle, North America was apparently the first continent to achieve its current approximate size and shape. Its geologic structure is built around a stable platform of Precambrian rock called the Canadian Shield. To the southeast are the Appalachian Mountains and to the west are the younger and much taller Cordilleras. These mountains extend the length of the continent and occupy about one-third of the total land area. The Rocky Mountains constitute the eastern Cordillera. The highest point is Mount McKinley. The Mississippi River basin, including its major tributaries, the Missouri and Ohio, occupies more than one-eighth of the continent's total area. Generally temperate climatic conditions prevail. Arable land accounts for about one-eighth of the land area and forests for about one-third. English, the primary language of the U.S., predominates, followed by Spanish; French is spoken in parts of Canada. Most of the continent's population of European descent is found in the U.S. and Canada. Intermarriage between whites and Indians was common in Mexico, and mestizos constitute about three-fifths of the Mexican population. North America has a mixture of developed, partly developed, and developing economies, adequate reserves of most metallic resources, and the world's largest reserves of cadmium, copper, lead, molybdenum, silver, and zinc. It is the world's leading food producer, largely because of mechanized and scientific farming in the U.S. and Canada. Among the continent's democratically governed states are Canada, Mexico, Costa Rica, and the U.S. The nations of North America have sought hemispheric unity as members of the Organization of American States, which also includes South American countries. They also sought stronger economic ties, and in 1992 Canada, the U.S., and Mexico signed the North American Free Trade Agreement (NAFTA), which called for the elimination of most tariffs and other trade barriers between the three countries. The first inhabitants were American Indians, who migrated from Asia about 20,000 years ago. The greatest pre-Columbian civilizations were in Mesoamerica (see Mesoamerican civilization) and included the Olmec, Maya, Toltec, and Aztec, who were conquered by the Spanish. The continent long remained sparsely settled and undeveloped. Beginning in the 17th century it underwent a profound transformation with the coming of Europeans and the Africans they introduced as slaves. The style of life became Latin American south of the Rio Grande and Anglo-American to the north, with enclaves of French culture in Canada and Louisiana. Slavery, practiced in the 16th–19th centuries, added a significant minority culture of African origin, especially in the U.S. and the Caribbean (see West Indies). The huge industrial economy of the U.S., its abundant resources, and its military strength give the continent considerable global influence. eb('http://www.britannica.com/eb/article-9110716/North-America','North America') For more information on North America, visit Britannica.com. Britannica Concise Encyclopedia. Copyright © 1994-2008 Encyclopædia Britannica, Inc.

North America the third largest continent, linked with South America by the Isthmus of Panama and bordering on the Arctic Ocean, the N Pacific, the N Atlantic, the Gulf of Mexico, and the Caribbean. It consists generally of a great mountain system (the Western Cordillera) extending along the entire W coast, actively volcanic in the extreme north and south, with the Great Plains to the east and the Appalachians still further east, separated from the Canadian Shield by an arc of large lakes (Great Bear, Great Slave, Winnipeg, Superior, Michigan, Huron, Erie, Ontario); reaches its greatest height of 6194 m (20 320 ft.) in Mount McKinley, Alaska, and its lowest point of 85 m (280 ft.) below sea level in Death Valley, California, and ranges from snowfields, tundra, and taiga in the north to deserts in the southwest and tropical forests in the extreme south. Pop.: 332 156 000 (2005 est.). Area: over 24 000 000 sq. km (9 500 000 sq. miles) HC_Discovery() Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005