The United States of America—commonly abbreviated as the United States, U.S.A., or U.S.—is a federal republic of fifty states in North America. The states include forty-eight mainland states that occupy the middle latitudes of the continent; Alaska at the northwestern extreme of North America; and Hawaii, an island state in the mid-Pacific Ocean. Mainland United States is bordered to the north by Canada, to the south by Mexico and the Gulf of Mexico, to the east by the Atlantic Ocean, and to the west by the Pacific Ocean.
The national capital of the United States is Washington, which is coextensive with the District of Columbia, a federal capital region created in 1790. The United States tends to be noted for its great variety, both in its physical environment and in the demographics of its population. By world standards, the United States is a relatively young country, being founded in 1776 as the first of the European colonies to successfully separate from its motherland and the first nation to be established on the premise that sovereignty rests with its citizens and not the government.
The United States emerged as a pre-eminent world power at the conclusion of the Second World War in the twentieth century. This status has pressured the principles and ideals of its founding fathers, and the country has struggled with the mantle of being a world power. However, the country continues to offer residents opportunities for unparalleled personal advancement of wealth compared to other countries; while the depletion of several resources and the environment and continuing social and economic inequality have served to perpetuate poverty and threaten the social and economic fabric of the country.
The United States is the fourth largest country by area, at more than twice the size of the European Union. The geography of the country is noted for the high mountains in the west and a vast central plain where the lowest point is in Death Valley at 282 feet below sea level and the highest peak is Denali at 20,320 feet above sea level. The country also has wide variance in topography, including deserts, rain forests, semiarid plains, volcanic topography in Hawaii, and various rugged mountain stretches and river valleys. The climate also depends on the location, with most of the country considered temperate but with a tropical climate in Hawaii and Florida and arctic in Alaska.
The country tends to be divided into six recognized regions based on the country's history of colonization by Europeans. These regions include New England, the mid-Atlantic, the South, the Midwest, the Southwest, and the West. While these regions have historical reasons for their founding, they tend to also have geographical and industrial similarities.
States considered part of the New England region include Connecticut, Main, Massachusetts, New Hampshire, Rhode Island, and Vermont. The mid-Atlantic region includes Delaware, Maryland, New Jersey, New York, Pennsylvania, and the city of Washington, D.C. While the South includes Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virginia.
The country's region known as the Midwest is comprised of the states Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin. The Southwest includes Arizona, New Mexico, Oklahoma, and Texas. While the American West, one of the more diverse regions, includes Alaska, Colorado, California, Hawaii, Idaho, Montana, Nevada, Oregon, Utah, Washington, and Wyoming.
The United States is a country rich in natural resources. These include coal, copper, lead, molybdenum, phosphates, rare earth elements, uranium, bauxite, gold, iron, mercury, nickel, potash, silver, tungsten, zinc, petroleum, natural gas, and timber. In terms of coal, the United States has the world's single largest coal reserves, commonly accounting for around 27 percent of the world's total.
The climate of the United States is diverse, with a range that spans from tropical conditions in areas such as Florida and Hawaii to arctic and alpine conditions in Alaska and across the Rocky Mountains. There is a strong gradient of temperatures for the continental United States, ranging from high temperatures in southern coastal states, where an annual average temperature exceeds 70 degrees Fahrenheit, to much cooler conditions in parts of the country along the Canadian border, where the season differences are as great as over 100 degrees Fahrenheit to below 50 degrees Fahrenheit between summer and winter.
Similarly, precipitation varies across the country and by season. Precipitation can measure more than 50 inches per year along the Gulf of Mexico, while in the intermountain West and Southwest, the levels of precipitation can be less than 12 inches. The West Coast areas tend to have distinct rainy seasons, while many parts of the Great Plains and Midwest experience late-spring peaks, and the Desert Southwest is influenced by summer's North American Monsoon.
The United States is subject to almost every kind of weather extreme, including severe thunderstorms, almost 1,500 tornadoes per year, an average of seventeen hurricanes that make landfall across the Gulf and Atlantic coasts, and drought conditions in 20 percent of the country at any given time. Similarly, the Pacific Basin experiences earthquakes, and the Western area experiences mudslides, forest fires, and flooding. Alaska also experiences permafrost in the most northerly part of the state, which is a major impediment to development in the region.
Alaska, Hawaii, the Pacific Northwest, and the Northern Mariana Islands experience volcanic activity, with some being deemed "decade volcanoes" by the International Association of Volcanology and Chemisty of the Earth's Interior. The most active volcanoes tend to be concentrated in the Aleutian arc and Hawaii. Volcanic activity often happens in the Hawaiian chain of islands, with one of the most well-known eruptions being the 1980 eruption of Mount St. Helens, which was famous for the devastation it caused.
The United States has a diverse range of geographic features, which offers various environments in which different flora and fauna live and thrive. This biodiversity has, since the expansion west and during the industrial developments of the twentieth century, been challenged. For example, the bison that once roamed the Great Plains region of the country live only in preserves. Other mammals include black bears, grizzlies, and polar bears, which are the largest carnivores in the country. The national bird and symbol of the United States is the bald eagle, also a protected species.
The country has more than 200,000 recognized native species, considered to be roughly 13 percent of the recognized species worldwide. This includes unique species of insects, lizards, birds, mammals, trees, and flowers. There are over 20,000 flowering species across the United States, many of which were imported from Europe.
More than 400 areas are protected and maintained by the National Park Service of the United States. There are also several projects of nature conservation across the country, especially as many native species in the United States are considered to be vulnerable, imperiled, critically imperiled, or already extinct. Some estimates suggest as much as 34 percent of plants and 40 percent of animals across the United States are at risk of extinction, while 41 percent of the ecosystems across the United States are at risk of collapse.
The government of the United States is a representative democracy with two legislative bodies: the Senate and the House of Representatives. The Senate consists of 100 seats, with two representatives from each of the fifty states. The House of Representatives consists of 435 seats, the occupants of which are elected from the fifty states. The government also consists of an executive branch, which includes the president as the head of the government and chief of state, and the judicial branch, which is made up of the Supreme Court, the U.S. Court of Appeals, the U.S. District Courts, and the state and county courts.
Federal elections occur every two years, on the first Tuesday after the first Monday in November. Every member of the House of Representatives and about one-third of the Senate is up for re-election in any given election year. State and local governments administer federal elections, with the specifics of how the election is conducted differing between states based on state-specific legislatures and administration beliefs.
Under the Tenth Amendment to the U.S. Constitution, the powers that are not under the Constitution granted to the federal government are given to the state government and the people. Each state government is modeled after the federal, including consisting of an executive, legislative, and judicial branch. The U.S. Constitution mandates the states maintain a republican form of government.
The legislative branch is established by Article I of the Constitution and consists of the House of Representatives and the Senate, which together form the United States Congress. Congress is granted the sole authority to enact legislation and declare war, the right to confirm or reject presidential appointments, and substantial investigative powers. The House of Representatives is made up of 435 elected members, which are voted from all fifty states in proportion to the population of those states. There are also six non-voting members to represent the District of Columbia, the Commonwealth of Puerto Rico, and the other territories of the United States.
The Senate is the other part of the legislative branch, composed of one hundred senators, with two voted for each state. Senators were previously chosen by state legislatures rather than by popular vote until the ratification of the Seventeenth Amendment in 1913. Since then, senators have been elected to six-year terms by the residents of each state. These terms are staggered so one-third of the Senate is up for reelection every two years. The vice president of the United States serves as the president of the Senate and casts a decisive vote in the event of a tie. There are two exceptions to this rule. The first is the case where the House must approve appointments to the vice presidency, and the second is the case of any treaty that involves foreign trade.
The executive branch is the president of the United States, who acts as the head of state and commander-in-chief of the armed forces, is responsible for implementing and enforcing laws written by Congress, and appoints the heads of federal agencies, including the cabinet. The vice president is also part of the executive branch, ready to assume the presidency if the need should arise. And the cabinet and independent federal agencies are responsible for the enforcement and administration of federal laws. The department and agencies are diverse, ranging from the Department of Defense, the Social Security Administration, the Securities and Exchange Commission, to the Environmental Protection Agency.
The cabinet, as a part of the executive branch, is an advisory body made of the fifteen heads of the executive departments. These heads are appointed by the president, with confirmation by the Senate, and tend to be the closest confidantes of the president, playing an important role in the president's decisions and in the line of the presidential succession. All members of the cabinet take the title secretary, except the head of the justice department, who is styled as the attorney general.
The judicial branch is established by Article III of the Constitution, which leaves it to Congress's discretion to determine the shape and structure of the federal judiciary, including the number of Supreme Court Justices. Through the article, Congress is given the power to establish courts inferior to the Supreme Court, which includes the district courts and the thirteen United States courts of appeals. Federal judges and justices serve no fixed terms and can only be removed through impeachment by the House of Representatives and conviction in the Senate, or else they can serve until retirement or death.
The courts are limited to trying actual cases or controversies, with a party required to show it has been harmed in order to bring suit. The courts do not issue advisory opinions on the constitutionality of laws or the legality of actions. Similar to Congress, the courts are capable of compelling the production of evidence and testimony through the use of subpoenas. Inferior courts are constrained by the decisions of the Supreme Court, with inferior courts required to apply the Supreme Court's interpretation to the facts of a given case and once the Supreme Court interprets a law.
The United States boasts one of the largest militaries in the world. In the simplest terms, the U.S. Armed Forces are composed of six military branches: Army, Navy, Air Force, Marine Corps, Coast Guard, and Space Force. The president of the United States is the commander-in-chief and is responsible for all final decisions of the armed forces, especially during times of war. The secretary of the Department of Defense (DoD) has control over the military and all of its branches, with the exception of the Coast Guard, which operates under the Department of Homeland Security. The armed forces employ more than 2 million civilians and military members, which leads many to hail the DoD as the largest "company" in the world.
Each branch of the armed forces is tasked with a unique mission in the overall mission objective of U.S. security and peace. In addition to these branches, the Army and Air National Guards also serve their own special functions. Through the branches, there tend to be three general categories of military people: active duty members, such as full-time soldiers and sailors; reserve and guard forces, which are often considered part-time members with civilian occupations and can be called to full-time military duty; and veterans and retirees, who are individuals who previously served in the armed forces.
Law enforcement in the United States follows a relatively decentralized structure, with federal authorities focused on violations of federal laws within their jurisdictions. Whereas at the local and state level, each of the fifty states has its own legislature with criminal statutes, and most of those states have police at several levels, including the municipal, county, and state levels.
There are approximately 15,766 police departments across the United States, with at least 12,650 at local levels. Depending on the jurisdiction, the members of these police services are required to complete different amounts of training, with some as little as 800 and others as many as 1,500 hours of training. Many of those agencies and departments operate a training academy. As of 2016, the number of officers employed at local police departments was around 468,000, representing 67 percent of the full-time sworn officers across the United States.
The Federal Bureau of Investigation (FBI) operates under the U.S. Department of Justice with the main functions of protecting the United States against terrorist attacks, foreign intelligence operations, and corruption at all levels; protecting civilian rights; combating transnational and national criminal organizations and enterprises, white-collar crime, and significant violent crime. Further, the FBI works to support federal, state, local, and international partners. The FBI employs around 35,000 employees, which includes special agents and support staff (intelligence analysts, language specialists, scientists, information technology specialists, and other professionals). For anyone working in the FBI, a four-year degree from a college or university is required before a recruit is trained at the FBI Academy at Quantico, Virginia.
The Drug Enforcement Agency (DEA) is similar to the FBI in that it operates under the U.S. Department of Justice and its officers are trained at Quantico, Virginia, in the same location as the FBI Academy. The DEA is tasked with enforcing the controlled substances laws and regulations of the United States and recommending and supporting non-enforcement programs aimed at reducing the availability of illicit controlled substances on the domestic and international markets.
The U.S. Customs and Border Protection (CBP) is a unified border agency within the Department of Homeland Security. CBP Combines inspectional workforces and broad border authorities of U.S. Customs, U.S. Immigration, Animal and Plant Health Inspection Service, and the U.S. Border Patrol. The top priority of the CBP is to keep terrorists and weapons from entering the United States, welcome all legitimate travelers, and enforce all applicable U.S. laws on immigration. This includes working to prevent narcotics, agricultural pests, smuggled goods, and those with outstanding criminal warrants from entering the country.
Immigration and Customs Enforcement (ICE) was created in 2003 with a mission to protect the United States and uphold public safety by identifying criminal activities and eliminating vulnerabilities that pose a threat to the nation's borders while enforcing economic, transportation, and infrastructure security. ICE is the largest investigative branch of the Department of Homeland Security.
Operating under the Department of Homeland Security, the United States Secret Service is mandated by statute and executive order to carry out its mission of protection and criminal investigations. The Secret Service works to protect the president and vice president, their families, heads of state, other designated individuals, the White House, the vice president's residence, Foreign Missions, and other buildings in Washington, D.C. The service investigates threats against these protectees, plans and implements security designs for designated National Special Security Events, and investigates violations of laws relating to counterfeiting and securities of the United States.
The United States has a large and technically advanced economy, considered the largest and most powerful world economy when measured in terms of gross domestic product (GDP). The economy operates as a mix of a free market economy with systems of a command economy in the government regulations enacted to restrict industry to protect specific industries, environments, and other special interests. The United States economy is also heavily involved in global trade, as both an exporter of raw materials and an importer of finished products.
The wealth of the United States and its economy is partially a reflection of rich natural resources and enormous agricultural output as much as it is a part of the country's highly developed and technical industrial and service sectors. The United States economy is both a source of and destination for venture capital, which helps the country sustain a heavily diversified economy that is capable of providing for the majority of its citizens and keeping up a high standard of living.
The main industries in the United States include petroleum, steel, motor vehicles, aerospace, telecommunications, chemicals, electronics, food processing, consumer goods, lumber, and mining. The main agricultural products of the United States include wheat, corn, other grains, fruits, vegetables, cotton, beef, pork, poultry, dairy products, and fish.
The United States is a product of the process of immigration. This immigration has shaped the history of the country and the demographics of the country, leading to a widely diverse population base that is relatively large by world standards while being dispersed enough to maintain a relatively low overall population density compared to other global countries. Especially when compared to a country like China, which is largely composed of an indigenous population, the United States has a high level of diversity, with some considering it to have the widest range of racial, ethnic, and cultural groups than any other single country.
In addition to the presence of Native Americans and the descendants of Africans taken as enslaved people to North America, the national character has been constantly redefined by tens of millions of immigrants who have come to the United States for various reasons. Due to the high level of immigration in the United States, the specific demographics and aging in the population are constantly changing.
The first official national flag of the United States was formally approved by the Continental Congress on June 14, 1777. This flag, known as the Stars and Stripes, was defined as thirteen stripes alternating red and white, with thirteen white stars on a field of blue in a constellation intended to represent the thirteen states of the union. The layout of the stars was left undefined, which spawned many patterns used by various flag makers, although the ring of stars, most likely designed by Congressman Francis Hopkinson, has been the most recognized of those designs.
In 1795, the flag changed when Congress enacted the second Flag Resolution to mandate new stars and stripes should be added to the flag to represent the new states of the union, Vermont and Kentucky. In 1818, after five more states had been admitted, Congress enacted the third and final Flag resolution, requiring the number of stripes on the flag to remain thirteen, and the number of stars should always reflect the number of states in the union, and any new star should be added to the flag on July 4 following the state's admission.
From 1777 to 1960, there have been twenty-seven versions of the flag, with twenty-five involving changes to the stars. The other two changes came in 1912, when President William Howard Taft standardized the proportions and size relative to the elements of the flag, and in 1934, the shades of the flags' colors were similarly standardized. The flag has no official assigned meaning, nor does it have any stated symbolism to the colors of the flag. This has led to several different interpretations of the meaning or symbolism of the elements of the flag.
For centuries, the native peoples and nations lived across the expanse of North America. In the sixteenth century, settlers from Europe began to move to North America, where they established colonies and began a process of displacing these native peoples. Explorers landed and established colonies for the Spanish at St. Augustine in Florida and the English at Roanoke in Virginia. The French landed and established a colony in Quebec, and the Dutch established a colony in present-day New York. Europeans continued to settle across North America throughout the next couple of centuries.
The colonization of North America was resisted by the native peoples of the continent. However, the Europeans worked to gain their land and were often outnumbered by the natives and had more powerful weapons. The European settlers also brought diseases that native peoples had not faced before, to devastating effect. A 1616 epidemic was estimated to kill around 75 percent of the native peoples in the New England region of North America. These kinds of devastating effects at the hands of disease were repeated as the Europeans expanded throughout the Americas.
From its establishment in 1776, the U.S. government signed nearly 400 treaties to the mid-nineteenth century to try and show the native peoples they wanted peace. However, most of these treaties were broken by the government, which went to lengths as far as sending in the military to forcibly remove the native peoples from their lands.
In 1776, the colonists living in the New England area drafted the Declaration of Independence, a document that laid out the grievances of the American colonies ruled by Great Britain. This would lead to the War of Independence, in which the colonists won their independence from Great Britain and formed a union of states based on a new constitution.
The new country, unshackled from its colonial overpowers, maintained the North American slave trade. By 1860, nearly four million enslaved people lived in the country, and more specifically in the South, where their labor was used to harvest sugar, cotton, and tobacco. In 1861, Abraham Lincoln was voted in as president and would work to end slavery in the country. This led to a division in the young country: the northern states, which in some cases had already outlawed the practice of slavery, agreed with Lincoln; the southern states, which largely relied on slave labor for their economy, did not want the practice of slavery to end.
The eleven southern states formed the Confederate States of America and led a civil war against the twenty-three northern states in defense of the slavery practice and their economy. Two years after the beginning of the war, in 1861, the Civil War ended with a Union victory and the passage of the Thirteenth Amendment, which abolished the practice of slavery. However, it did not end racism, and formerly enslaved peoples and their descendants struggled with discrimination and discriminatory policies.
The twentieth century would be the century in which the United States established itself as an economic and military power. The population of the country grew from approximately 5 million people in 1800 to nearly 80 million people in 1900. The early 1900s saw large waves of immigration as people left Europe and related areas for a chance at a new opportunity. This further diversified the country's population and demographics.
Following the world wars, specifically during the 1950s, 1960s, and 1970s, the country gained a reputation as a progressive country, especially compared to the country's peers. Further, the country pushed to be a technological leader, potentially exemplified best by the 1969 landing of the first human on the moon. Throughout these decades, there also came a fight for civil rights for Americans of all backgrounds, which led to historic firsts for people of color through the decades.
The late twentieth century saw the United States struggle with its ideological conflict with the former Soviet Union. This would lead to United States' involvement in civil wars in Korea and Vietnam. The period of non-violent tensions between the United States and the former Soviet Union would end in the late twentieth century with the fall of the Soviet Union, now the Russian Federation. The United States would also engage in the Gulf War against the country of Iraq.