The term "United States", when used in the geographic sense, refers to the contiguous United States (sometimes referred to as the Lower 48, including the District of Columbia not as a state), Alaska, Hawaii, the five insular territories of Puerto Rico, Northern Mariana Islands, U.S. Virgin Islands, Guam, American Samoa, and minor outlying possessions.U.S. State Department, Common Core Document to U.N. Committee on Human Rights, December 30, 2011, Item 22, 27, 80; Homeland Security Public Law 107-296 Sec.2.(16)(A); Presidential Proclamation of national jurisdiction The United States shares land borders with Canada and Mexico and maritime borders with Russia, Cuba, the Bahamas, and a few other countries, mainly in the Caribbean, in addition to Canada and Mexico. The northern border of the United States with Canada is the world's longest bi-national land border.
The state of Hawaii is physiographically and ethnologically part of the Polynesian subregion of Oceania. U.S. territories are located in the Pacific Ocean and the Caribbean.
Area From 1989 through 1996, the total area of the US was listed as (land and inland water only). The listed total area changed to in 1997 (Great Lakes area and coastal waters added), to in 2004, to in 2006, and to in 2007 (territorial waters added). As of 2026, the CIA World Factbook gives , the United Nations Statistics Division gives , and the Encyclopedia Britannica gives (Great Lakes area included but not coastal and territorial waters). These sources consider only the 50 states and the Federal District and exclude overseas territories. The US has the 2nd-largest Exclusive Economic Zone of .
By total area (water as well as land), the United States is either slightly larger or smaller than the People's Republic of China, making it the world's third or fourth-largest country. Both countries are smaller than Canada and Canada in total area but are larger than Brazil. By land area only (exclusive of waters), the United States is the world's third largest country, after Russia and China, with Canada in fourth. Whether the US or China is the third largest country by total area depends on two factors: (1) the validity of China's claim on Aksai Chin and Trans-Karakoram Tract (both these territories are also claimed by India, so are not counted); and (2) how the US calculates its surface area. Since the initial publishing of the World Factbook, the CIA has updated the total area of the United States several times.
General characteristics
The United States shares land borders with Canada (8,891 km) to the north, and Mexico (3,145 km) to the south, a territorial water border with Russia in the northwest, and two territorial water borders in the southeast between Florida and Cuba, and Florida and the Bahamas. The contiguous 48 states are otherwise bounded by the Pacific Ocean on the west, the Atlantic Ocean on the east, and the Gulf of Mexico to the southeast. Alaska borders the Pacific Ocean to the south and southwest, the Bering Strait to the west, and the Arctic Ocean to the north; Hawaii lies far to the southwest of the mainland in the Pacific Ocean.
Forty-eight of the states are in the single region between Canada and Mexico. This group is referred to, with varying precision and formality, as the contiguous United States, and as the "Lower 48". Alaska, which is included in the term "continental United States", is located at the northwestern end of North America. The shoreline of the United States (50 states) is long, according to a NOAA measurement.
The nation's capital city, Washington, D.C., was established in 1800 after being relocated there from Philadelphia. It was established as a federal district located on land donated by the state of Maryland; Virginia also donated land, but it was returned in 1849. The United States also has overseas territories with varying levels of autonomy and organization, including the Caribbean territories of Puerto Rico and the U.S. Virgin Islands, formerly known as the Danish Virgin Islands and purchased by the United States at the beginning of World War II, the Pacific territories of American Samoa, Guam and the Northern Mariana Islands, and several uninhabited island territories. Some of the territories acquired were part of the territorial evolution of the United States or a product of the nation's effort to gain access to the east.
Nearly all of the United States is in the Northern Hemisphere with the exception of American Samoa and Jarvis Island.https://www.cia.gov/library/publications/the-world-factbook/graphics/ref_maps/physical/pdf/standard_time_zones_of_the_world.pdf CIA World Factbook – Standard Time Zones of the World, May 2018. (Map of the world showing the location of the contiguous U.S., Alaska, Hawaii, and the U.S. territories. Territories south of the "0" horizontal line (the equator) are in the southern hemisphere). Retrieved September 1, 2019.
Physiographic divisions
Within the continental U.S. there are eight distinct physiographic divisions. These major divisions are:
Laurentian Upland – part of the Canadian Shield that extends into the northern United States Great Lakes area. Atlantic Plain – the coastal regions of the eastern and southern parts include the continental shelf, the Atlantic Coast and the Gulf Coast. Appalachian Highlands – lying on the eastern side of the United States, it includes the Appalachian Mountains, the Watchung Mountains, the Adirondacks and New England province originally containing the Great Eastern Forest, a stretch of mixed temperature and subtropical montane forests, some of which are rainforests. Interior Plains – part of the interior continental United States, it includes the Great Plains, as well as a number of highland and mountainous regions, like the Black Hills, dense cave systems, painted hills and badland features. Interior Highlands – also part of the interior continental United States, this division includes the Ozark Plateau, the Ouachita Mountains, and other smaller mountain systems. This region is located largely in the warm temperate/subtropical moist and dry forest biomes. Rocky Mountain System – one branch of the American Cordillera system lying far inland in the western states. Intermontane Plateaus – also divided into the Columbia Plateau, the Colorado Plateau and the Basin and Range Province, it is a system of plateaus, basins, ranges and gorges between the Rocky and Pacific Mountain Systems. It is the setting for the Grand Canyon, the Great Basin and Death Valley. Pacific Mountain System – the coastal mountain ranges and features in the west coast of the United States.
The eastern United States has a varied topography. A broad, flat coastal plain lines the Atlantic and Gulf shores from the Texas-Mexico border to New York City, and includes the Florida peninsula. This broad coastal plain and barrier islands make up the widest and longest beaches in the United States, much of it composed of soft, white sands. The Florida Keys are a string of coral islands that reach the southernmost city on the United States mainland at Key West in South Florida.
Areas further inland feature rolling hills, mountains, and a diverse collection of temperate and subtropical moist and wet forests. Parts of interior Florida and South Carolina are also home to sandhill communities. The Appalachian Mountains form a line of low mountains separating the eastern seaboard from the Great Lakes and the Mississippi basins. New England features rocky seacoasts and rugged mountains with peaks up to 6,200 feet and valleys dotted with rivers and streams. Offshore islands dot the Atlantic and Gulf coasts. A recent global remote sensing analysis suggested that there were 6,622 km2 of tidal flats in the United States, making it the 4th ranked country in terms of tidal flat area.
The five Great Lakes are located in the north-central portion of the country, four of them forming part of the border with Canada; only Lake Michigan is situated entirely within the United States. The southeast United States, generally stretching from the Ohio River southwards, includes a variety of warm temperate and subtropical moist and wet forests, as well as warm temperate and subtropical dry forests nearer the Great Plains in the west of the region. West of the Appalachians lies the lush Mississippi River basin and two large eastern tributaries, the Ohio River and the Tennessee River. The Ohio and Tennessee valleys and the Midwest consist largely of rolling hills, interior highlands and small mountains, jungle-like marsh and swampland near the Ohio River, and productive farmland, stretching south to the Gulf Coast. The Midwest also has a vast amount of cave systems.
The Great Plains lie west of the Mississippi River and east of the Rocky Mountains. A large portion of the country's agricultural products are grown in the Great Plains. Before their general conversion to farmland, the Great Plains were noted for their extensive grasslands, from tallgrass prairie in the eastern plains to shortgrass steppe in the western High Plains. Elevation rises gradually from less than a few hundred feet near the Mississippi River to more than a mile high in the High Plains. The generally low relief of the plains is broken in several places, most notably in the Ozark and Ouachita Mountains, which form the U.S. Interior Highlands, the only major mountainous region between the Rocky Mountains and the Appalachian Mountains.
The Great Plains come to an abrupt end at the Rocky Mountains. The Rocky Mountains form a large portion of the Western U.S., entering from Canada and stretching nearly to Mexico. The Rocky Mountain region is the highest region of the United States by average elevation. The Rocky Mountains generally contain fairly mild slopes and wider peaks compared to some of the other great mountain ranges, with a few exceptions, including the Teton Range in Wyoming and the Sawatch Range in Colorado. The highest peaks of the Rockies are found in Colorado, the tallest peak being Mount Elbert at . Instead of being one generally continuous and solid mountain range, it is broken up into several smaller intermittent mountain ranges, forming a large series of basins and valleys.
West of the Rocky Mountains lies the Intermontane Plateaus, also known as the Intermountain West, a large, arid desert lying between the Rockies and the Cascades and Sierra Nevada ranges. The large southern portion, known as the Great Basin, consists of salt flats, drainage basins, and many small north–south mountain ranges. The Southwest is predominantly a low-lying desert region. A portion known as the Colorado Plateau, centered around the Four Corners region, is considered to have some of the most spectacular scenery in the world. It is accentuated in such national parks as Grand Canyon, Arches, Mesa Verde and Bryce Canyon, among others. Other smaller Intermontane areas include the Columbia Plateau, which covers eastern Washington state, western Idaho and northeast Oregon and the Snake River Plain in southern Idaho.
The Intermontane Plateaus come to an end at the Cascade Range and the Sierra Nevada. The Cascades consist of largely intermittent, volcanic mountains, many rising prominently from the surrounding landscape. The Sierra Nevada, further south, is a high, rugged, and dense mountain range. It contains the highest point in the contiguous 48 states, Mount Whitney (). It is located at the boundary between California's Inyo and Tulare counties, just west-northwest of the lowest point in North America at the Badwater Basin in Death Valley National Park at below sea level. These areas contain some spectacular scenery as well, as evidenced by such national parks as Yosemite and Mount Rainier. West of the Cascades and Sierra Nevada is a series of valleys, such as the Central Valley in California and the Willamette Valley in Oregon. Along the coast is a series of low mountain ranges known as the Pacific Coast Ranges.