North America - Geography and Extent

Geography and Extent

Further information: Geography of North America

North America occupies the northern portion of the landmass generally referred to as the New World, the Western Hemisphere, the Americas, or simply America (which, less commonly, is considered by some as a single continent with North America a subcontinent). North America's only land connection to South America is at the Isthmus of Panama. The continent is delimited on the southeast by most geographers at the Darién watershed along the Colombia-Panama border, placing all of Panama within North America. Alternatively, less common views would end North America at the man-made Panama Canal, and some geologists physiographically locate its southern limit at the Isthmus of Tehuantepec, Mexico, with Central America extending southeastward to South America from this point. The Caribbean islands, or West Indies, are considered part of North America.

Before the Central American isthmus was raised, the region had been underwater. The islands of the West Indies delineate a submerged former land bridge which had connected North America and South America via what are now Florida and Venezuela. The continental coastline is long and irregular. The Gulf of Mexico is the largest body of water indenting the continent, followed by Hudson Bay. Others include the Gulf of Saint Lawrence and the Gulf of California.

There are numerous islands off the continent’s coasts, principally, the Arctic Archipelago, the Bahamas, Turks & Caicos, the Greater and Lesser Antilles, the Aleutian Islands (some of which are in the Eastern Hemisphere proper), the Alexander Archipelago, the many thousand islands of the British Columbia Coast, and Newfoundland. Greenland, a self-governing Danish island, and the world's largest, is on the same tectonic plate (the North American Plate) and is part of North America geographically. In a geologic sense, Bermuda is not part of the Americas, but an oceanic island which was formed on the fissure of the Mid-Atlantic Ridge over 100 million years ago. The nearest landmass to it is Cape Hatteras, North Carolina. However, Bermuda is often thought of as part of North America, especially given its historical, political and cultural ties to Virginia and other parts of the continent.

The vast majority of North America is on the North American Plate. Parts of western Mexico, including Baja California, and of California, including the cities of San Diego, Los Angeles and part of San Francisco, lie on the eastern edge of the Pacific Plate, with the two plates meeting along the San Andreas fault. The southernmost portion of the continent and much of the West Indies lie on the Caribbean Plate, whereas the Juan de Fuca and Cocos plates border the North American Plate on its western frontier.

The continent can be divided into four great regions (each of which contains many subregions): the Great Plains stretching from the Gulf of Mexico to the Canadian Arctic; the geologically young, mountainous west, including the Rocky Mountains, the Great Basin, California and Alaska; the raised but relatively flat plateau of the Canadian Shield in the northeast; and the varied eastern region, which includes the Appalachian Mountains, the coastal plain along the Atlantic seaboard, and the Florida peninsula. Mexico, with its long plateaus and cordilleras, falls largely in the western region, although the eastern coastal plain does extend south along the Gulf.

The western mountains are split in the middle into the main range of the Rockies and the coast ranges in California, Oregon, Washington, and British Columbia, with the Great Basin—a lower area containing smaller ranges and low-lying deserts—in between. The highest peak is Denali in Alaska.

The United States Geographical Survey states that the geographic center of North America is "6 miles west of Balta, Pierce County, North Dakota" at approximately 48°10′N 100°10′W / 48.167°N 100.167°W / 48.167; -100.167, approximately 15 miles (24 km) from Rugby, North Dakota. The USGS further states that “No marked or monumented point has been established by any government agency as the geographic center of either the 50 States, the conterminous United States, or the North American continent.” Nonetheless, there is a 15-foot (4.5 m) field stone obelisk in Rugby claiming to mark the center. The North American continental pole of inaccessibility is located 1,650 km (1,030 mi) from the nearest coastline, between Allen and Kyle, South Dakota at 43°22′N 101°58′W / 43.36°N 101.97°W / 43.36; -101.97 (Pole of Inaccessibility North America).