Die USA setzen sich aus 50 Bundesstaaten zusammen. Die Gesamtfläche des Landes beträgt 9,809,155 km². Im Norden hat die Grenze zu Kanada eine Länge von 8893 km, während die Grenze zu Mexiko im Süden 3326 km beträgt. Im Osten werden die Staaten vom Atlantik begrenzt und im Westen vom Pazifik. Die Entfernung zwischen New York und Los Angeles misst fast 5000 km.
On the east side of the American continent the Appalachian mountain range stretches from Cape Gaspe in Canada to Atlanta, Georgia.
In the east the Appalachians are formed by a low plateau, the Piedmont, and a steeply rising ridge, the Blue Ridge with Mount Mitchell (2037 meters) being the highest point.
The central part consists of several parallel ridges which lie between broad valleys, the Valley and Ridge Region.
The western side ends at a high steep edge, called the Alleghany Mountains.
The flat central part of the United States is lifted under influence of the Rocky Mountains on the west side. Thus a predominantly flat landscape was created that rises gradually to the foot of the Rocky Mountains.
These vast plains, the prairies, are stretching from Ohio and Missouri in the east, through Illinois and Wisconson, Minnesota, Iowa and northern Missouri, and then spreads out in Central Texas, Oklahoma, Kansas and eastern Nebraska and South and North Dakota.
The lower portion west of the Mississippi is almost entirely transformed into agricultural fields, the 'Corn Belt'. The high part is a dry steppe at the foot of the Rocky Mountains at about 1500 meters altitude. Large rivers such as Missouri, Arkansas and Platte River have carved wide valleys herein. The large plain in the states of Missouri and Arkansas is interrupted by the Ozark Plateau, an extension of the Appalachians.
The Gulf Coast is a large alluvion area that continues in the peninsula of Florida. Along the Atlantic coast these sandy plains continue to Cape Cod.
To the west the Cordillera Mountains rise 2000 meters above the Great Plains. This vast mountain range stretches from the far north of the American continent, the heavily glaciated Brooks Range to the Sierra Madre del Sur in Mexico, actually even further in the Andes chain in South America.
The eastern chain of the Cordillera are the Brooks Range, Mackenzie Mountains, the Rocky Mountains and the Sierra Madre Oriental. West of these ranges are a number of plateaus. Lakes were created by ridges in this plateau. In some cases these lakes had no outflow to the sea, so salt lakes such as Great Salt Lake, were formed.
The 'Great Plains' lie west of this line that clearly divides the North American continent in two: the 508-mm rainfall line, one of the major geographical divisions in the United States. This line, which is almost right through the center of the country from north to south separates the more hospitable east of the dry west, which is in the rain shadow of the Rocky Mountains.
The land between the Rocky Mountains and the Sierra Nevada in the west is dry. In this part of the country also lies 'the bottom of the United States', Death Valley. This ancient lake bed, now a dessert of more than 200 km long, lies 830 meters below sea level.
Rivers carved vast canyons on these plateaus, with the Grand Canyon of the Colorado River being the most famous. The Grand Canyon in Arizona is the deepest canyon in the world, 446 km long with an average depth of 1.6 kilometers.
In the west, this plateau ends at a mountain range with a steep eastern side and a less steep western side: the Alaska Range, St. Elias Mountains, Coast Range, Cascade Range, Sierra Nevada and Sierra Madre Occidental.
In the north of the continent, this chain forms a real fjord coast, where big Alaskan glaciers scroll to the sea. Further south are coastal mountains, in the U.S. States a concluded mountain range that closes the Willamette Valley and the Valley of California. Further south these mountains separate the Gulf of California from the Pacific Ocean.
Alaska, the 49th state is a different story from the landscape point of view. Alaska is composed of ice. Under the ice and snow layers, the soil is frozen to a depth of 90 meters. Even in summer, when the sun is practical shining continuously, the soil is frozen below a depth of 60 centimeters. In the north temperatures can drop till 40° C below zero, whilst in the south the winters are more bearable. In Central Alaska Mount McKinley (6200 meters) is the highest mountain in North America. Outside Alaska Mount Whitney in California's is the highest mountain with 4418 meters.
Even Hawaii, the fiftieth state, is not to compare with other states. The eight large and about one hundred small islands are spread over a length of 2500 km in the Pacific Ocean. The island closest to the American coast, is about 3200 km from San Francisco. The largest island is Hawaii has five volcanoes, two of which are still active. The 4200 meters high crater of Mauna Loa is the largest active volcano in the world.
Rivers and lakes
Water management of the United States is primarily determined by topography. The major basins lie in the central lowlands.The Great Lakes form an important hydrographic area at the border of the United States and Canada. With a total area of approximately 250,000 square kilometres this is the largest freshwater basin in the world.
The lakes are interconnected by rivers and are linked via the St. Lawrence River to the sea. The biggest difference in height exists between the Erie Lake and Lake Ontario at the Niagara Falls. In terms of passing watermass these falls can be counted among the largest in the world.
The heights of the American Falls and Canadian Falls are not as spectacular, respectively 52 and 48 meters.
In Yosemite National Park lies one of the world's highest waterfalls, the Ribbon (491 meters).
From the eastern edge of the Appalachians a number of short rivers flow into the Atlantic Ocean. The largest basin in the U.S. is the Mississippi Basin. It includes the central lowlands to the south of the Great Lakes, west of the Appalachians and much of the east side of the Rocky Mountains. The source of the Mississippi river lies on the Mesabi Range and the river is navigable from Anthony Falls in Minneapolis. The decay is low and after the inclusion of the Missouri and Ohio, the river is a one kilometer wide stream. The Rio Grande, flowing through one of the driest areas of the Great Plains, has great significance for the irrigation.
The rivers to the west of the Rocky Mountains often lie in deep canyons through the plateaus of the Great Basin. Most famous is of course the Grand Canyon, which was carved by the Colorado River.