Terrain

The U.S. has an extremely varied geography, particularly in the West. The eastern seaboard has a coastal plain which is widest in the south and narrows in the north. The coastal plain does not exist north of New Jersey, although there are glacial outwash plains on Long Island, Martha's Vineyard, and Nantucket. In the extreme southeast, Florida is home to the ecologically unique Everglades.

Beyond the coastal plain, the rolling hills of the Piedmont region end at the Appalachian Mountains, which rise above 6,000 feet (1,830 m) in North Carolina, Tennessee, and New Hampshire. From the west slope of the Appalachians, the Interior Plains of the Midwest are relatively flat and are the location of the Great Lakes as well as the Mississippi-Missouri River, the world's 4th longest river system.[10] West of the Mississippi River, the Interior Plains slope uphill and blend into the vast and often featureless Great Plains.

The abrupt rise of the Rocky Mountains, at the western edge of the Great Plains, extends north to south across the continental U.S., reaching altitudes over 14,000 feet (4,270 m) in Colorado.[11] In the past, the Rocky Mountains had a higher level of volcanic activity; nowadays, the range only has one area of volcanism (the supervolcano underlying Yellowstone National Park in Wyoming, possibly the world's largest volcano), although rift volcanism has occurred relatively recently near the Rockies' southern margin in New Mexico.[12] Dozens of high mountain ranges, salt flats such as the Bonneville Salt Flats, and valleys are found in the Great Basin region located west of the Rockies and east of the Sierra Nevada, which also has deep chasms, including the Snake River. At the southwestern end of the Great Basin, Death Valley lies 282 feet (86 m) below sea level, the second lowest dry land on Earth. It is the lowest point in the Western Hemisphere and is situated near the Mojave Desert.

North of the Great Basin and east of the Cascade Range in the Northwest is the Columbia River Plateau, a large igneous province shaped by one of the largest flood basalts on Earth. It is marked by dark black rocks. Surrounding the Four Corners region lies the Colorado Plateau, named after the Colorado River, which flows through it. The Plateau is generally high in elevation, has highly eroded sandstone, and the soil is a blood red in some locations. Many national parks, such as Arches, Bryce Canyon, Grand Canyon, and Zion are in the area. West of the Great Basin, the Sierra Nevada mountain range has Mount Whitney, the highest peak in the coterminous U.S. Along the Pacific coast, the Coast Ranges and the volcanic Cascade Range extend from north to south across the country. The northwestern Pacific coast shares the world's largest temperate rain forest with Canada.

Alaska has numerous mountain ranges, including Mount McKinley (Denali), the highest peak in North America. Numerous volcanoes can be found throughout the Alexander and Aleutian Islands extending south and west of the Alaskan mainland.

The Hawaiian islands are tropical, volcanic islands extending over 1,500 miles (2,400 km), and consisting of six larger islands and another dozen smaller ones that are inhabited.