United States of America (USA)

The USA, officially known as the United States of America, and often referred to simply as the U.S. or U.S.A., is a federal republic consisting of 50 states located in North America. The country spans a vast expanse of territory, with the 48 conterminous states situated in the middle latitudes of the continent, Alaska occupying the northwestern extreme of North America, and the island state of Hawaii situated in the mid-Pacific Ocean. The contiguous states share borders with Canada to the north, the Atlantic Ocean to the east, the Gulf of Mexico and Mexico to the south, and the Pacific Ocean to the west. In terms of land area, the United States is the fourth largest country in the world, behind only Russia, Canada, and China.

Washington, the national capital of the United States, is located in the District of Columbia, which was established as the federal capital region in 1790.

The United States is renowned for its remarkable diversity, which is reflected in its physical environment that ranges from the Arctic to the subtropical, and from the moist rainforest to the arid desert. The country features rugged mountain peaks, as well as vast flat prairies. Despite having a large population by global standards, the overall population density in the United States is relatively low. The country boasts some of the world’s largest urban concentrations, alongside extensive areas that are almost uninhabited.

The United States is home to a highly diverse population, which has largely resulted from a massive and sustained global immigration. Unlike China, which largely incorporated indigenous peoples, the United States has a greater degree of diversity, with a wide range of racial, ethnic, and cultural types. Along with the presence of Native Americans, the national character has been enriched by the tens of millions of immigrants who have come to America seeking greater social, political, and economic opportunities. It is worth noting that while the terms “America” and “Americans” are often used to refer to the United States and its citizens, respectively, they can also be used to describe North, South, and Central America and their citizens as a whole.

The United States is the world’s foremost economic power, measured in terms of gross domestic product (GDP). The nation’s wealth is a reflection of its rich natural resources, vast agricultural output, and highly developed industry. Although it is relatively self-sufficient in many areas, the United States remains the most important single factor in world trade, due to the sheer size of its economy. The country’s exports and imports represent a significant proportion of the world total. Moreover, the United States has a significant impact on the global economy as a source and a destination for investment capital. The country maintains an economic life that is more diversified than any other on Earth, ensuring that most of its citizens enjoy one of the highest standards of living in the world.

Compared to many countries, the United States is a relatively young nation, having been founded less than 250 years ago. It was the first European colony to successfully break away from its motherland and establish a government based on the idea that sovereignty belongs to its citizens, not the government. During its early years, the country was focused on expanding its territory, growing its economy, and grappling with social debates that ultimately led to a civil war and a long period of healing. In the 20th century, the United States emerged as a world power, but it has not always embraced this role easily, and its founders’ principles have been tested by the pressures of being a dominant force. Despite offering its residents unparalleled opportunities for personal advancement and wealth, the country faces significant challenges such as depletion of resources, environmental contamination, and social and economic inequality.

For more information on the District of Columbia, see the article on Washington. Other major cities in the United States are discussed in articles on Boston, Chicago, Los Angeles, New Orleans, New York City, Philadelphia, and San Francisco. Political units associated with the United States include Puerto Rico (see the article on Puerto Rico) and several Pacific islands (discussed in articles on Guam, Northern Mariana Islands, and American Samoa).


The physical environment of the United States is shaped by two major factors: geologic and atmospheric. The geologic factors determine the primary patterns of landforms, mineral resources, and drainage, and to a lesser extent, soil. The atmospheric factors determine climate, weather, and the distribution of plants, animals, and soil to a large extent. While these factors are interrelated to some degree, they produce distinct patterns on a map, effectively creating two separate geographies.

People of the United States

Despite being a relatively new member of the global community, with a history spanning less than 250 years, the growth of the United States since the 18th century has been unparalleled. The promise of the New World as a land of refuge and opportunity was realized dramatically in the 20th century, when the United States emerged as a world power. With a population surpassed only by China and India, the United States is also characterized by an extraordinary diversity in ethnic and racial ancestry. Immigrants from all over the world were drawn to the United States seeking a better life, with 60 million people arriving on U.S. shores in the 18th and 19th centuries alone. This pool of foreign-born persons is unmatched by any other nation, as many arrived seeking to escape political or economic hardship, while others were attracted by the abundance of natural resources and cheap land.

In addition to international migration, Americans have also migrated internally with great vigor, demonstrating a restlessness that thrived on the open lands and frontier. Migration patterns initially ran from east to west and from rural areas to cities, and later shifted from the South to the Northeast and Midwest in the 20th century. Since the 1950s, however, movement has been primarily from cities to outlying suburbs and from aging northern metropolises to the growing urban agglomerations of the South, Southwest, and West.


The United States boasts the largest economy in the world in terms of gross domestic product (GDP) and has historically ranked among the world’s top nations in GDP per capita. Despite having less than 5 percent of the world’s population, the country accounts for about one-fifth of global economic output.

Given the scale of the U.S. economy, it holds a dominant position in international trade. The country’s exports make up over 10 percent of the world’s total, and its influence on other economies is significant as a source of investment capital. Similar to how direct investment by the British was a key factor in the 19th-century U.S. economic growth, foreign investment by U.S. firms is now a major driving force behind the economic prosperity of Canada, Mexico, China, and many other countries across Latin America, Europe, and Asia.

Transportation of the United States

The remarkable mobility of people and goods in the United States is reflected in the country’s economic and social landscape. The widespread transportation network has turned the expansive geography into a surprisingly connected and cohesive social and economic environment. The flexibility to move freely is often credited as a key factor in the dynamism of the U.S. economy. However, mobility also has negative consequences, including the decay of older urban areas, increased traffic congestion, heightened environmental pollution, and reduced support for public transportation systems.

Roads and railroads:

The Dwight D. Eisenhower System of Interstate and Defense Highways, commonly known as the Interstate System, is a critical component of the transportation network in the United States, spanning 45,000 miles (72,000 km) and connecting nearly 90% of cities with populations of at least 50,000. This system, which carries approximately 20% of the country’s motor traffic, was constructed in the 1950s and is used extensively by the roughly 90% of households that own at least one automobile or truck. While private vehicles dominate transportation in most metropolitan areas, public transit and rail systems are essential in the country’s most populous cities. Major cities such as New York City, Chicago, Philadelphia, and Boston have a majority of home-to-work commuters traveling by public transportation.

Once the primary mode of transportation for both passengers and freight, railroads in the United States have since ceded much of their traffic to trucks due to government regulation and increased competition. Today, railroads move around one-third of intercity freight traffic, with the most common items transported being coal, grain, chemicals, and motor vehicles. Many rail companies stopped offering passenger service by 1970, leading to the creation of the National Railroad Passenger Corporation (Amtrak), a government corporation that now operates a 21,000-mile (34,000-km) system serving over 500 stations throughout the country.

Water and air transport

The United States has an extensive network of navigable waterways that revolve around the Mississippi River system in the interior, the Great Lakes-St. Lawrence Seaway system in the north, and the Gulf Coast waterways along the Gulf of Mexico. Barges transport more than two-thirds of domestic waterborne traffic, carrying petroleum products, coal and coke, and grain. The Port of South Louisiana, the Port of Houston, Texas, the Port of New York/New Jersey, and the Port of New Orleans are the largest ports in tonnage handled.

Since the mid-20th century, air traffic in the United States has experienced remarkable growth. From 1970 to 1999, passenger traffic on certified air carriers increased by 373 percent. This growth largely occurred after airline deregulation, which began in 1978. There are over 14,000 public and private airports, with Atlanta and Chicago having the busiest airports in terms of passenger traffic. Memphis, Tennessee, which serves as the hub of package-delivery company Federal Express, and Los Angeles have the highest freight cargo traffic.

Cultural life

Sir Ernst Hans Josef Gombrich, a renowned art historian, once stated that there is no such thing as “art”, only artists. This statement is relevant when studying or defining the diverse culture of the United States.

The American culture is shaped by unique individuals, rather than impersonal forces, and is not limited to established art forms or institutions. Many of the most talented American artists have chosen to make their art far from the parades and rallies of worldly life, focusing on the interior life of the mind and heart that shapes and precedes shared “national” experience. One of the biggest quarrels in American culture has been between the values of mass, democratic, popular culture and those of a refined elite culture accessible only to the few. The growth of mass communication technologies has created a potential audience for stories, music, and theater larger than anyone could previously have dreamed of. The dream of a common culture directed not to an aristocracy but to all men and women began in a spirit of hope, but by the middle of the century, many people thought that the control of culture had passed into the hands of advertisers, people who used the new machines to produce a bland homogenization of culture.

History of the United States

The continental United States had been discovered prior to Columbus’s voyages, likely by multiple parties. Upon Columbus’s arrival, he found the New World inhabited by people who had likely migrated from Asia to North America through the Bering Strait 20,000 to 35,000 years earlier. These Indigenous peoples, commonly referred to as Indians, had spread and occupied all regions of the New World. The prevailing culture of each region was largely determined by the available resources. For example, fish and sea mammals were the main food sources for coastal peoples, while the American bison was a staple for Plains Indians. Corn was a staple for Indians of the Southwest. The procurement of these foods called for different techniques depending on the local resources.

Raw materials also influenced the material culture of the respective regional groups. Indians transported goods by human carrier and used dogs to pull sleds or travois. Rafts, boats, and canoes were used where water facilities were available. The horse, imported by the Spanish in the early 16th century, was quickly adopted by the Indians, especially by the buffalo-hunting Indians of the Great Plains. House types varied among different Indian culture groups. Clothing, crafts, weapons, tribal economic, social, and religious customs also varied.

At the time of Columbus’s arrival, there were an estimated 1.5 million American Indians in what is now the continental United States, though estimates vary greatly. To understand the role and impact of American Indians on the subsequent history of the United States, it is important to understand the differentiating factors between Native American peoples. American Indians as a whole exercised an important influence on the civilization brought from Europe to the New World. Their contributions include food, herbs, articles of manufacture, methods of raising crops, war techniques, words, folklore, and ethnic infusions. The conflict caused by “white” expansionism and Indian resistance is one of the most tragic chapters in the history of the United States.


Also Known As America • U.S. • United States of America • U.S.A.
Head Of State And Government President: Joe Biden
Capital Washington, D.C.
Population 331,449,281; (2023 est.) 339,277,0002
Currency Exchange Rate 1 US dollar equals 0.909 euro
Form Of Government federal republic with two legislative houses (Senate [100]; House of Representatives [4351])
Official Language none
Official Religion none
Official Name United States of America
Total Area (Sq Km) 9,834,6333
Total Area (Sq Mi) 3,797,1733
Monetary Unit dollar (U.S.$)
Population Rank (2023) 3
Population Projection 2030 358,633,000
Density: Persons Per Sq Mi (2023) 89.3
Density: Persons Per Sq Km (2023) 34.5
Urban-Rural Population Urban: (2018) 82.3% • Rural: (2018) 17.7%
Life Expectancy At Birth Male: (2022) 78.4 years • Female: (2022) 82.8 years
Literacy: Percentage Of Population Age 15 And Over Literate Male: (2000–2004) 95.7% • Female: (2000–2004) 95.3%
Gni (U.S.$ ’000,000) (2021) 23,393,117
Gni Per Capita (U.S.$) (2021) 70,430
1Excludes five nonvoting delegates from the District of Columbia, the U.S. Virgin Islands, American Samoa, the Northern Mariana Islands, and Guam and a nonvoting resident commissioner from Puerto Rico.2Includes military personnel overseas.3Total area (excluding 42,334 sq mi [109,645 sq km] of coastal water and 76,804 sq mi [198,921 sq km] of territorial water) equals 3,677,649 sq mi (9,525,067 sq km), of which land area equals 3,531,925 sq mi (9,147,643 sq km), inland water area equals 85,631 sq mi (221,783 sq km), and Great Lakes water area equals 60,093 sq mi (155,641 sq km).

Did You Know?

  • Annually, the U.S. spends more on its military than the next seven highest-ranking countries in military spending combined.
  • The internet was first conceptualized in the United States.
  • Dwarf-tossing in establishments that sell liquor is illegal in Florida.
  • The U.S. owns the GPS (Global Positioning System).
  • A cat served as honorary mayor for 20 years in Talkeetna, Alaska.