Geography/the Americas

Now it's time to begin physical geography, beginning with the Americas—the continents North and South America, which are located between the Pacific and Atlantic Oceans. Markers indicate where an interactive map is available displaying the particular place.

North America

Overview

North America extends in a north-south direction, following the course of the Rocky Mountains (location) and other mountain ranges (the "Cordillera"). North America's southern limit is the Panama Canal, and its northern end is the Canadian Archipelago and the Arctic Ocean.

The southern part of North America—Central America—is tropical, and while it includes some mountains and volcanoes, has less varied terrain, and lacks the broad mountain ranges and long rivers that are present to the north. In Mexico, at which point the continent broadens, the highest peaks reach approximately 20,000 feet (6,100 m) and the center of the continent is covered in dry highlands, where there are numerous mountain ranges. If you traveled north along the course of the Rocky Mountains, you would notice that the mountain range changes in width in various places, with the determinant of this factor being how broadly the term "Rocky Mountains" is applied.

In the U.S. and Canada, there is a noticeable trend: high and mountainous in the west, but lower in the east. The highest peak, which is on the western side of the North American continent, goes by two names: Mount McKinley, its former name, and Denali, the name more recently assigned to the mountain. Although Denali is the highest in North America, it is lower than the highest peak in South America (that being Aconcagua); and, of course, Denali is lower than the highest mountain peaks in the Himalayas of Asia. Denali is in the state of Alaska in the U.S.

Coastline

On the eastern side of the North American continent, large gulfs and bays create an indented coastline; the largest indents are the Gulf of Mexico (location) and the Hudson Bay, although Cape Cod and Chesapeake Bay are also notable. The western coast, on the other hand, has only one inlet of comparable size, the Gulf of California, which comes between most of Mexico and the Baja California peninsula.

West

Various smaller geographical features along both coasts exist, often as parts, ends, or continuations of estuaries. The San Francisco/San Pablo Bay marks the end of the Sacramento River, along with some other, smaller streams like Alameda Creek and Coyote Creek. The San Francisco Bay (location) has a very narrow connection to the Pacific Ocean: the Golden Gate. (The Golden Gate Bridge crosses the Golden Gate.) To the south of the San Francisco Bay is the wider, less enclosed Monterey Bay, and farther south again is an island group, the Channel Islands, that is separated from the mainland of North America by a strait. Many rivers flow from the Sierra Nevada (location) west (or, more specifically, often southwest) into the Central Valley (location), then meet around the central part of this valley, and finally flow west as part of the Sacramento Delta to the San Pablo Bay, which is connected to the San Francisco Bay and the ocean.

East

On the East Coast is Chesapeake Bay and other, similar features; Long Island, on the eastern side of the New York City, extends outward into the Atlantic Ocean, and so does Cape Cod to the north. The Gulf of Saint Lawrence, farther north again, marks where the St. Lawrence River meets the sea, and ultimately the Atlantic Ocean; to the east of the Gulf of St. Lawrence is the large island of Newfoundland.

In the southeast of the North American continent, the Florida Peninsula (location) stretches toward the Bahamas and Cuba. It is low-lying and contains numerous lakes and beaches. The largest of the lakes, which is controlled by levees, is Lake Okeechobee. Other large lakes in Florida (George, Monroe, and Jesup) constitute part of the St. John's River, a river that flows north in the state from the Orlando area to Jacksonville, where it turns east to the Atlantic Ocean. Beaches in Florida extend across much of both sides of the peninsula in the form of barrier islands. On the Atlantic Coast an Intracoastal Waterway (expanded for watercraft) separates the mainland from the sandy barrier islands. On the Gulf Coast, the barrier islands, which are common in the southwest of the peninsula, give way to wetlands north of Tampa Bay.

The Outer Banks of North Carolina extend east into the Atlantic Ocean and are an extension of low-lying wetland regions. However, notable geographic features continue in earnest with the Delmarva Peninsula, which extends south with the Chesapeake Bay on its western side and the Atlantic Ocean on its eastern side, with a narrow passage between the peninsula and the rest of Virginia.

In New York City, at the southern end of the Hudson River, there are a number of geographic features. The largest local island, Long Island's western end is in the city and it extends dozens of miles east. To the northeast in New England is the Cape Cod Peninsula, which extends and curves east and north. In its vicinity are two islands, Martha's Vineyard and Nantucket.

Nova Scotia extends both to the north and south following its narrow isthmus from New Brunswick. Prince Edward Island sits off the coast of New Brunswick to the west of Nova Scotia. The island of Newfoundland is north of Nova Scotia, and marks (if traveling north) the final large island in Canada before Baffin Island and its archipelago.

Arctic

Greenland is northeast of Canada and has some high mountain peaks that pass 10,000 feet (3,000 m). Greenland's western coast has many inlets, called fjords, and has some habitable land. Inland, however, is a large ice sheet similar to the one in Antarctica, and this ice sheet covers most of the island. West of Greenland is the Canadian Archipelago which stretches north and includes some large but sparsely populated islands.

Interior

Great Plains and Great Lakes

North of the Gulf of Mexico are two important landforms, the Mississippi River Basin directly north and the Appalachian Mountains (location) to the northeast. The Mississippi River and its longest tributary, the Missouri River, dominate the central part of North America, and the location these rivers cover marks one of the world's largest flat areas, lying between the Rockies and the Appalachians. The Appalachians, while long, are not nearly as high as the Rockies, however, and in height they are comparable to Australia's Great Dividing Range. Flowing from the Plains north toward the Arctic Ocean, in the opposite direction of the Mississippi, is the Mackenzie River, which flows through two large lakes, the Great Slave Lake and the Great Bear Lake, before it meets its final destination.

The Great Bear and Great Slave Lakes are not to be confused with the five Great Lakes (location) on the U.S.-Canadian border. Northwest of the Appalachians, the lakes in this group—Lake Superior, Lake Michigan, Lake Huron, Lake Ontario, and Lake Erie—are among the largest lakes in the world. The five Great Lakes are all in close proximity to each other.

Mountain ranges

While the term Rocky Mountains is sometimes applied to the general mountain ranges on the western side of the United States, especially by those from the eastern part of the country, more specific terms can be used for the various mountain ranges that go in a north-south direction through the western part of the U.S. and Canada. In the U.S. state of California, going from north to south on the eastern end of the state, is the high Sierra Nevada mountain range. The highest peak in this range is Mount Whitney, which is over 14,000 feet (4,300 m) high. The western side of the Sierra Nevada gradually climbs from the low Central Valley to its peak, and then quickly goes downhill on the eastern side, making not only the construction of roads, but also the use of mountain passes, difficult. The Sierra Nevada becomes the Cascade Mountains in northern California; and the Cascades, a more volcanic mountain range, in turn continues north into Washington state, and it includes such high peaks as Mount Rainier and Mount Saint Helens.

West of the Central Valley, a large agricultural plain in central California, are a group of mountain ranges called the Coastal, or Coast, Ranges. These are much lower than the Sierras (with mountain peaks generally in the low thousands of feet high) but in places have dramatic scenery. The Coastal Ranges extend north from the L.A. region in Southern California north to the San Francisco Bay, where this bay, along with the Sacramento Delta — which connects to the Central Valley — bring an end to the southern part of the range. It continues north of the Bay north to the Cascades.

Inland but still on the west-central side of the North American continent are a couple large, dramatic canyons, like the Grand Canyon, which is approximately 5,000 feet (1,500 m) deep, and the similarly deep Hells Canyon, which is north and east of the Grand Canyon. Yosemite Valley, which is between these two larger canyons, is also a few thousand feet deep, a depth not rare for valleys and canyons in this region.

Climate

Several factors contribute to the varying climates of North America, but the most important is the topographical variation across the United States and Canada. The numerous ranges that extend north to south on the western side of the continent, but then curve to the west in Alaska, act as a shield that protects the western coastline from the cold air of the polar vortex. Even when cold air penetrates the Rocky Mountains, it is unable to also penetrate the Sierra Nevada, keeping regions west of this mountain range warm with stable, predictable weather. Consequently, California in particular, but also to a lesser extent Oregon, Washington, and the Canadian province British Columbia, have climates ideal for human habitation.

Due to the temperature of the waters of the Pacific Ocean, which is relatively warm at higher latitudes, such as British Columbia, but relatively low at the lower latitudes of southern California, precipitation decreases from north to south along the Pacific coastline. While coastal cities such as Seattle typically receive heavy precipitation, especially in winter, California's coastline is wet in the north but dry in the south. In addition to the effect on precipitation, the Pacific Ocean also keeps coastal towns and cities relatively cool when compared to inland locations.

The regions east of the Rocky Mountains, however, have completely different climates, as cold air from the polar vortex is able to move south through the eastern part of the continent during winter, only to be pushed away for warm summers. This causes much of the Great Plains/Midwest region to have a "continental" climate with warm to hot summers and cold winters. Going south toward the Gulf of Mexico, however, winter temperatures become relatively mild.

The Appalachians are not high enough to prevent cold from reaching the eastern United States, and even Florida at the southeastern end of the country can receive cold weather during winter when the remnants of the polar vortex move south into the region.

Summary

Overall, North America is a continent with a little of everything. Even surrounding it are notable geographical features — the island of Greenland is the world's largest island, and to the west of the continent is the world's largest ocean.

Quiz

Complete the North America quiz.

South America

Angel Falls

South America is a smaller continent than its northern neighbor, but it is still a great, expansive landmass dominated by tropical forests, high mountains, and lower plains.

The northern tip of the continent is near the location of the Panama Canal and the Darien Gap (a place on the North America/South America border where no roads exist). The narrow isthmus of Panama widens to the countries of Colombia and Venezuela, marking the northern end of the South American continent. The mountain range that starts in this region and continues south is the Andes Mountain Range, or just the Andes, and it extends all the way across the continent. There are large plains, forests, basins, deserts, and highlands east of the Andes, but the portion of South America west of the Andes is relatively narrow. On the western side of the Andes is the Atacama Desert, and on the eastern side of the range are the Guiana Highlands and the Amazon Basin, toward the north, and toward the south Brazil's highland regions and the great expanse of Pampas in Argentina. In the far south is Tierra del Fuego (location); this land at South America's southern tip is not only associated with fire, but also cold, stormy oceans.

Returning to the northern end of South America, to the east of the Darien Gap is a tropical region slightly north of the equator. (The country of Venezuela occupies much of this region.) In this region to the east Lake Maracaibo (location) is located.

The Atlantic Ocean and the Caribbean Sea form a coastline along the northern side of the tropical region, gradually going southeast toward an eastward "land's end" in Brazil. Between South America's easternmost point and Lake Maracaibo is the Guiana Highlands region, where there are some fairly high, though flat-topped, mountains. The mountains provide an ideal environment for waterfalls: Angel Falls, which comes off the side of one of these flat-topped mountains, is the highest waterfall in the world.

To the south of the Guiana Highlands is the Amazon River Basin. The Amazon and many other rivers gather here and go east from the Andes toward the Atlantic Ocean. This tropical rainforest region is around the location of the equator. The basin has a low elevation, unlike the destination where the rivers begin, in the Andes. The Andes mark the divide between the Amazon River and tributaries and any rivers that flow in the opposite direction, to the west. At the top of the Andes is a high plateau that itself is covered with mountains. Compared to the Amazon Basin, the region at the top of the Andes is cold and dry, but it does have some lakes. Lake Titicaca is known for its high elevation and the people that live around (and, on) the lake.

The land west of the Andes is tropical in the north, but south of the equator, it quite quickly becomes very dry — so dry that it hardly receives any rain at all. This is the Atacama Desert, which is in the country of Chile.

Meanwhile, on the other side of the Andes, the tropical land gradually changes to grassland. Along the way are some highlands, and in Rio de Janeiro, for example, it is quite mountainous. To the south, however, is Uruguay, which is much flatter. South again in Argentina, the grassland is good ranching country, but going south again, gives way to desert. In Chile, however, the opposite is the case; as one goes south, it gets wetter.

The southern end of the continent is colder and is quite close to Antarctica. The continent is narrow (in the east/west direction) here. The Strait of Magellan and Tierra del Fuego mark the southern end of South America, before the Southern Ocean and then Antarctica's northern end. East of South America's southern tip are some islands, including the Falkland Islands and the South Georgia Islands.

Climate

Despite being smaller than North America, South America is still the location of a wide variety of climates. The cold current of the Pacific causes the equatorial part of the western coast, the Atacama Desert, to have a desert climate, with dry climates extending to Santiago and, to a lesser extent, the Galapagos Islands west of the mainland but belonging to the country of Ecuador.

The Andes itself is the location of a mostly dry climate at the highest points, descending into tropical rainforest to the east. The tropical rainforest of the eastern portion of the continent gives way to Pampas and ultimately desert in the south, with cooler climates without such high annual precipitation totals as Sao Paulo and regions to the north of Brazil's largest cities.

The Pacific coast of Chile does, however, become wetter going south. South of Santiago near the coast, climates are relatively mild, contrasting with the dry Atacama Desert to the north.

Quiz

Complete the South America quiz.