According to getzipcodes, the USA borders Canada to the north and Mexico to the south. Outside the contiguous state territory in southern North America are the states of Alaska and Hawaii.
The east-west extension between the Atlantic and Pacific Oceans is around 4,500 km, the north-south extension around 2,700 km. Geomorphologically, the area can be subdivided into four major units: the coastal plain on the Atlantic Ocean and the Gulf of Mexico, the Appalachians, the Inner Plains and the Cordilleras. The highest mountain in North America is the Denali in the Alaska range with 6,198 m above sea level, the deepest depression the Death Valley with 86 m below sea level.
The Atlantic coastal plain, which widens south from the mouth of the Hudson River in New York, includes the Florida peninsula and merges into the Gulf Coast plain in northwest Florida. In the west follows the Appalachian mountain range, which extends for around 2,500 km in a south-west-north-east direction. The Rump Mountains are made up of ridges, long valleys and plateaus. In the north the White Mountains in Mount Washington reach 1,917 m above sea level, in the south the Blue Ridge in Mount Mitchell rises to 2,037 m above sea level. The Interior Plains are made up of the Mississippi and Missouri electricity systemsdrained to the south. The Central Lowland extends around the Great Lakes. The Great Plains to thewest consist of spacious plateaus, which are interrupted by individual strata and mountain islands (Ozark Mountains, Black Hills).
The Pacific West is taken by the Cordilleras. They extend in a north-south direction and are up to 1,500 km wide. Typical is a longitudinal division into the eastern chain of the Rocky Mountains with heights over 4,000 m above sea level, the intermontane plateaus, basins and valleys as well as the Pacific mountain ranges.
Inner areas include: the Columbia Plateau to the north, cut by the Columbia River, Snake River, and other rivers; the Great Basin, which is divided into mountain ranges and depressions such as those of the Great Salt Lake and Death Valley (Basin and Range Province); the Colorado Plateau, a plateau whose strata are exposed to a depth of 1,800 m from the Colorado River in the Grand Canyon. To the west, the Sierra Nevada (Mount Whitney 4,421 m, highest mountain in the USA outside of Alaska) and the Cascade Range join as parts of the Pacific mountain ranges(Mount Rainier 4,392 m). They are separated from the lower Coast Ranges by a depression with the more than 700 km long California Long Valley and the Puget-Willamette Depression in the north. The subsoil of the western Cordilleras is unstable.
Volcanic eruptions like that of Mount Saint Helens (1980) as well as earthquakes in Alaska (1964) and repeated until recently in California are expressions of plate shifts in the depths of the western continental margin. Part of the plate boundary is exposed in the San Andreas Fault.
Waters: The inland waters cover 204 084 km 2 (about 2% of the land area). Lakes are particularly found in the Pleistocene glaciation area in the north. The Great Lakes, which apart from Lake Michigan partly belong to Canada (USA’s share of the Great Lakes 156 050 km 2), also extend there. The mountains are also rich in lakes, and salt lakes are widespread in the dry west.
Due to the watersheds in the foothills, the catchment areas of the open oceans are relatively small. The runoff to the Gulf of Mexico through the Mississippi and Missouri river system (3.2 million km 2), on the other hand, is very large. There and in the humid east, e.g. B. on the Tennessee River, flood protection is necessary. The expansion and regulation of many rivers have created numerous waterways for inland navigation. The southwestern United States, on the other hand, suffers from water scarcity due to high water consumption by agriculture and large cities as well as droughts.
The climate is determined by the latitude, the area and the north-south extension of the mountains. The temperatures are cool-temperate in the north, subtropical warm-temperate in the south, and tropical on the southern tip of Florida. Inside there is a continental climate with strong contrasts between summer and winter. Abrupt temperature changes are caused by air ingress from the north or south; Polar air can reach Florida. In the Interior Plains, contrasts in air pressure and temperature often result in tornadoes (over 1,000 per year), like hurricanes can cause severe damage on the Gulf Coast and the southern Atlantic coast. Due to the prevailing westerly winds, the highest amounts of precipitation fall on the windward sides of the mountains (2,000 to 3,000 mm per year), while on the leeward side there is drought (sometimes less than 250 mm of precipitation per year). Precipitation increases again east of the climatic dry line (roughly along 98 ° west longitude) to over 500 mm and in the Atlantic east reaches values of more than 1 000 mm per year.
In the humid east forest predominates: in the north coniferous forest, which merges into a species-rich deciduous forest and mixed forest to the south; Spruce-fir, beech-maple or oak- hickory stands are common. The natural vegetation in the dry interior (prairie) and in large parts of the intermontane basins form grasslands with different vegetation densities. Deserts have developed in the southwest. The mountains in the west are mostly forested, in the southern area there are woody formations with hard-leaved plants. Alaska is part of the boreal coniferous forest and tundra.