Landforms of North America

Landforms of North America
Name	North American Landforms
Region	North America
Highest	Denali
Longest river	Missouri River
Largest lake	Great Lakes
Notable features	Rocky Mountains, Appalachian Mountains, Great Plains, Canadian Shield, Mackenzie River

Landforms of North America North America's landscape spans from the Arctic Baffin Island archipelagos through the Great Plains to the Caribbean Greater Antilles, producing a patchwork of Canadian Shield cratons, folded belts like the Appalachian Mountains, and young orogens such as the Rocky Mountains and the Sierra Nevada (U.S.). Tectonic interactions along the Pacific Plate margin that include the San Andreas Fault and the Cascadia subduction zone combine with Pleistocene glaciation tied to the Laurentide Ice Sheet to shape coastlines near Hudson Bay, estuaries like the St. Lawrence River, and interior basins such as the Colorado Plateau. Human histories — from indigenous polities of the Mississippian culture and Ancestral Puebloans to modern states including the United States and Canada — follow these physiographic templates and river corridors like the Mississippi River and Mackenzie River.

Overview and Definitions

Physiographic classification of North America uses criteria developed by the United States Geological Survey and Canadian counterparts such as Natural Resources Canada to delineate provinces like the Interior Plains and shields including the Canadian Shield. Key definitions distinguish shields (exposed Precambrian basement like Laurentia), platforms (sedimentary cover near the Gulf of Mexico), and orogens (folded mountain belts exemplified by the Appalachian Mountains and the Cordilleran orogeny). Sea-level change histories tied to the Pleistocene Epoch and legal frameworks from treaties such as the Treaty of Guadalupe Hidalgo have influenced coastal mapping and resource claims in areas including the Arctic Ocean shelf.

Major Physiographic Regions

The continent is often divided into provinces: the eastern Appalachian Mountains and adjacent Atlantic Coastal Plain, the central Interior Plains and Great Plains, the western Cordillera including the Rocky Mountains and Sierra Nevada (U.S.), and the northern Canadian Shield with the Hudson Bay basin. Peripheral regions include the insular complexes of the Caribbean Sea and the volcanic arcs of the Aleutian Islands and Cascades Volcanoes. Continental margins reflect contrasts between passive margins like the Atlantic Seaboard and active margins along the Pacific Coast of North America where features such as the San Andreas Fault and Queen Charlotte Fault dominate.

Mountains and High Plateaus

Major mountain systems—Rocky Mountains, Appalachian Mountains, Sierra Madre Occidental, and Sierra Madre Oriental—show a range of origins from uplift associated with the Laramide Orogeny to ancient Appalachian thrusting during the Alleghanian orogeny. High plateaus and mesas include the Colorado Plateau, the Mexican Plateau, and portions of the Columbia Plateau formed by Columbia River Basalt Group eruptions. Glaciated peaks such as Denali and Mount Logan preserve cirques and arêtes, while volcanic edifices like Mount St. Helens, Mount Rainier, and Popocatépetl illustrate ongoing subduction-related magmatism.

Plains, Prairies, and Interior Lowlands

The Great Plains and Interior Plains extend from the Canadian Prairies through the Central United States to the Llano Estacado, featuring loess mantles, aeolian dunes, and fluvial terraces shaped by systems like the Missouri River and Arkansas River. The Mississippi River valley hosts alluvial plains and deltas at the Gulf of Mexico influenced by sediment load and subsidence, while the Hudson Bay Lowlands and Boreal Shield transition zones reflect postglacial rebound and peatland formation tied to sites such as James Bay.

Coastal Landforms and Margins

Coastlines vary from the drowned river valleys of the Chesapeake Bay and estuary systems like the Delaware Bay to barrier islands along the Gulf Coast of the United States and the Outer Banks. Fjorded coasts occur in Alaska and British Columbia, while carbonate platforms and reefal structures are present in the Florida Keys and Belize Barrier Reef. Coastal plain geology interacts with storms and sea-level change evident in events such as Hurricane Katrina impacts on the Mississippi Delta and ongoing shoreline modification near New Orleans and Galveston, Texas.

Glacial and Periglacial Features

Pleistocene glaciation by the Laurentide Ice Sheet and Cordilleran ice shaped moraines, drumlins, eskers, and proglacial lakes including the erstwhile Glacial Lake Agassiz, whose remnants include the Red River Valley. Periglacial landscapes in the Canadian Arctic Archipelago, Greenland margins, and the Alaska North Slope feature patterned ground, pingos, and continuous permafrost influenced by modern warming noted in studies across Nunavut and Yukon. Glacial refugia and meltwater routing influenced human migration corridors linked to hypotheses about crossings near the Bering Land Bridge and archaeological sites such as Clovis.

Rivers, Lakes, and Drainage Systems

Major drainage networks include the Mississippi River–Missouri River system, the transboundary Mackenzie River draining into the Beaufort Sea, and the Yukon River connecting interior basins to the Bering Sea. The Great Lakes system—Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario—represents the largest freshwater complex influenced by the Saint Lawrence River outlet and engineering works like the Welland Canal and St. Lawrence Seaway. Closed basins such as the Great Basin (U.S.) and terminal lakes like Great Salt Lake and Salton Sea reflect aridity patterns tied to the Sierra Nevada (U.S.) rain shadow and historical diversions exemplified by projects like the Hoover Dam.

Category:Geography of North America