The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands,[j] and 326 Indian reservations. It is the third-largest country by both land and total area.[d] The United States shares land borders with Canada to its north and with Mexico to its south. It has maritime borders with the Bahamas, Cuba, Russia, and other nations.[k] With a population of over 331 million,[e] it is the third most populous country in the world. The national capital is Washington, D.C., and the most populous city and financial center is New York City.
Paleo-aboriginals migrated from Siberia to the North American mainland at least 12,000 years ago, and advanced cultures began to appear later on. These advanced cultures had almost completely declined by the time the Europeans had arrived in North America, who subsequently began to colonize the continent. The United States emerged from the Thirteen British Colonies when disputes with the British Crown over taxation and political representation led to the American Revolution (1765–1784), which established the nation's independence. In the late 18th century, the U.S. began expanding across North America, gradually obtaining new territories, sometimes through war, frequently displacing Native Americans, and admitting new states. By 1848, the United States spanned the continent from east to west. The controversy surrounding the practice of slavery culminated in the secession of the Confederate States of America, which fought the remaining states of the Union during the American Civil War (1861–1865). With the Union's victory and preservation, slavery was abolished by the Thirteenth Amendment.
By 1900, the United States had become the world's largest economy, and the Spanish–American War and World War I established the country as a world power. After Japan's surprise attack on Pearl Harbor in 1941, the U.S. entered World War II on the Allied side. The aftermath of the war left the United States and the Soviet Union as the world's two superpowers. During the Cold War, both countries engaged in a struggle for ideological dominance but avoided direct military conflict. They also competed in the Space Race, which culminated in the 1969 American spaceflight that first landed humans on the Moon. Simultaneously, the civil rights movement led to legislation abolishing state and local Jim Crow laws and other codified racial discrimination against African Americans. The Soviet Union's dissolution in 1991 ended the Cold War, leaving the United States as the world's sole superpower. The September 11 attacks in 2001 resulted in the United States launching the war on terror, which included the War in Afghanistan (2001–2021) and the Iraq War (2003–2011).
The United States is a federal republic with three separate branches of government, including a bicameral legislature. It is a liberal democracy and market economy; it ranks high in international measures of human rights, quality of life, income and wealth, economic competitiveness, and education; and it has low levels of perceived corruption. It has high levels of incarceration and inequality, allows capital punishment, and lacks universal health care. As a melting pot of cultures and ethnicities, the U.S. has been shaped by centuries of immigration.
The United States is a highly developed country, and its economy accounts for approximately a quarter of global GDP and is the world's largest by GDP at market exchange rates. By value, the United States is the world's largest importer and second-largest exporter. Although it accounts for just over 4.2% of the world's total population, the U.S. holds over 30% of the total wealth in the world, the largest share held by any country. The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, NATO, and is a permanent member of the United Nations Security Council. The country makes up more than a third of global military spending and is the foremost military power in the world and a leading political, cultural, and scientific force.
China,[k] officially the People's Republic of China (PRC),[l] is a country in East Asia. It is the world's most populous country with a population exceeding 1.4 billion people.[m] China spans five geographical time zones[n] and borders fourteen countries by land,[o] the most of any country in the world, tied with Russia. China also has a narrow maritime boundary with the disputed Taiwan.[p][q] Covering an area of approximately 9.6 million square kilometers (3,700,000 sq mi), it is the world's third largest country by total land area.[r] The country consists of 23 provinces,[p] five autonomous regions, four municipalities, and two Special Administrative Regions (Hong Kong and Macau). The national capital is Beijing, and the most populous city and financial center is Shanghai.
Modern Chinese trace their origins to a cradle of civilization in the fertile basin of the Yellow River in the North China Plain. The semi-legendary Xia dynasty in the 21st century BCE and the well-attested Shang and Zhou dynasties developed a bureaucratic political system to serve hereditary monarchies, or dynasties. Chinese writing, Chinese classic literature, and the Hundred Schools of Thought emerged during this period and influenced China and its neighbors for centuries to come. In the third century BCE, Qin's wars of unification created the first Chinese empire, the short-lived Qin dynasty. The Qin was followed by the more stable Han dynasty (206 BCE – 220 CE), which established a model for nearly two millennia in which the Chinese empire was one of the world's foremost economic powers. The empire expanded, fractured and re-unified, was conquered and reestablished, absorbed foreign religions and ideas, and made world-leading scientific advances, such as the Four Great Inventions: gunpowder, paper, the compass, and printing. After centuries of disunion following the fall of the Han, the Sui (581–618) and Tang (618–907) dynasties reunified the empire. The multi-ethnic Tang welcomed foreign trade and culture that came over the Silk Road and adapted Buddhism to Chinese needs. The early modern Song dynasty (960–1279) became increasingly urban and commercial. The civilian scholar-official or literati used the examination system and the doctrines of Neo-Confucianism to replace the military aristocrats of earlier dynasties. The Mongol invasion established the Yuan dynasty in 1279, but the Ming dynasty (1368–1644) re-established Han Chinese control. The Manchu-led Qing dynasty nearly doubled the empire's territory and established a multi-ethnic state that was the basis of the modern Chinese nation, but suffered heavy losses to foreign imperialism in the 19th century.
The Chinese monarchy collapsed in 1912 with the Xinhai Revolution, when the Republic of China (ROC) replaced the Qing dynasty. In its early years of the Republic, the country became unstable known as the Warlord Era before reunifying the nation in 1928 under the nationalist government while the alliance between the Kuomintang (KMT) and the Chinese Communist Party (CCP) had fallen apart that led to a civil war that lasted two decades. Japan invaded China in 1937, starting the Second Sino-Japanese War and temporarily halting the civil war. The surrender and expulsion of Japanese forces from China in 1945 left a power vacuum in the country, which led to renewed fighting between the CCP and the Kuomintang. The civil war ended in 1949[s] with the division of Chinese territory; the CCP established the People's Republic of China on the mainland while the Kuomintang-led ROC government retreated to the island of Taiwan.[t] Both claim to be the sole legitimate government of China, although the United Nations has recognized the PRC as the sole representation since 1971. From 1959 to 1961, the PRC implemented an economic and social campaign called the Great Leap Forward, that resulted in a sharp economic decline and an estimated 15 to 55 million deaths, mostly through man-made famine. From 1966 to 1976, the turbulent period of political and social chaos within China known as the Cultural Revolution, led to greater economic and educational decline, with millions being purged or subjected to either persecution or politicide based on categories. Since then, the Chinese government has rebuked some of the earlier Maoist policies, conducting a series of political and economic reforms since 1978, which has greatly raised Chinese standards of living, and increased life expectancies.
China is currently governed as a unitary Marxist–Leninist one-party socialist republic by the CCP. China is a permanent member of the United Nations Security Council and a founding member of several multilateral and regional cooperation organizations such as the Asian Infrastructure Investment Bank, the Silk Road Fund, the New Development Bank, the Shanghai Cooperation Organisation, and the RCEP, and is a member of the BRICS, the G8+5, the G20, the APEC, and the East Asia Summit. It ranks among the lowest in measurements of civil liberties, government transparency, freedom of the press, freedom of religion and ethnic minorities. The Chinese authorities have been criticized by human rights activists and non-governmental organizations for human rights abuses, including political repression, mass censorship, mass surveillance of their citizens, and violent suppression of protests.
Making up around one-fifth of the world economy, China is the world's largest economy by GDP by purchasing power parity, the second-largest economy by nominal GDP, and the second-wealthiest country. The country is one of the fastest growing major economies and is the world's largest manufacturer and exporter. China is a recognized nuclear-weapon state with the world's largest standing army by military personnel and second-largest defense budget. China is considered to be a potential superpower due to its large markets, high innovation, economic potential, growing military strength, and influence in international affairs.
Russia (Russian: Россия, tr. Rossiya, pronounced [rɐˈsʲijə]), or the Russian Federation,[c] is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, covering over 17,098,246 square kilometres (6,601,670 sq mi), and encompassing one-eighth of Earth's inhabitable landmass. Russia extends across eleven time zones sharing land boundaries with fourteen countries, more than any other country but China.[d] It is the ninth-most populous country in the world and the most populous country in Europe, with a population of 146 million. The country's capital and largest city is Moscow, the largest city entirely within Europe. Saint Petersburg is Russia's cultural centre and second-largest city. Other major urban areas include Novosibirsk, Yekaterinburg, Nizhny Novgorod and Kazan.
The East Slavs emerged as a recognisable group in Europe between the 3rd and 8th centuries CE. The medieval state of Kievan Rus' arose in the 9th century, and in 988 adopted Orthodox Christianity from the Byzantine Empire. Rus' ultimately disintegrated, with the Grand Duchy of Moscow growing to become the Tsardom of Russia. By the early 18th century, Russia had vastly expanded through conquest, annexation, and exploration to become the Russian Empire, the third-largest empire in history. The monarchy was abolished following the Russian Revolution in 1917, and the Russian SFSR became the world's first constitutionally socialist state. Following a civil war, the Russian SFSR established the Soviet Union with three other republics, as its largest and the principal constituent. The country underwent a period of rapid industrialisation at the expense of millions of lives. The Soviet Union played a decisive role in the Allied victory in World War II, and was a superpower and rival to the United States during the Cold War. The Soviet era saw some of the most significant technological achievements of the 20th century, including the world's first human-made satellite and the launching of the first human into space.
Following the dissolution of the Soviet Union in 1991, the newly independent Russian SFSR renamed itself the Russian Federation. In the aftermath of the constitutional crisis of 1993, a new constitution was adopted, and Russia has since been governed as a federal semi-presidential republic. Since his election in 2000, Vladimir Putin has dominated Russia's political system and Russia has experienced democratic backsliding, shifting into an authoritarian state. Russia ranks high in international measurements of standard of living, household income and education; having universal healthcare and a free university education. However, Russia also ranks low in measurements of human rights, freedom of the press, economic freedom, and has high levels of perceived corruption.
The Russian economy is the world's ninth-largest by nominal GDP and the sixth-largest by PPP. It has the world's largest stockpile of nuclear weapons, with the fifth-highest military expenditure. Russia's extensive mineral and energy resources are the world's largest, and it is among the leading producers of oil and natural gas globally. It is a permanent member of the United Nations Security Council, a member of the G20, the SCO, BRICS, the APEC, the OSCE and the WTO, as well as the leading member of the CIS, the CSTO, and the EAEU. Russia is home to 30 UNESCO World Heritage Sites.
India, officially the Republic of India (Hindi: Bhārat Gaṇarājya), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast, it shares land borders with Pakistan to the west;[f] China, Nepal, and Bhutan to the north; and Bangladesh and Myanmar to the east. In the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives; its Andaman and Nicobar Islands share a maritime border with Thailand, Myanmar, and Indonesia. The nation's capital city is New Delhi.
Modern humans arrived on the Indian subcontinent from Africa no later than 55,000 years ago. Their long occupation, initially in varying forms of isolation as hunter-gatherers, has made the region highly diverse, second only to Africa in human genetic diversity. Settled life emerged on the subcontinent in the western margins of the Indus river basin 9,000 years ago, evolving gradually into the Indus Valley Civilisation of the third millennium BCE. By 1200 BCE, an archaic form of Sanskrit, an Indo-European language, had diffused into India from the northwest. Its evidence today is found in the hymns of the Rigveda. Preserved by a resolutely vigilant oral tradition, the Rigveda records the dawning of Hinduism in India. The Dravidian languages of India were supplanted in the northern and western regions. By 400 BCE, stratification and exclusion by caste had emerged within Hinduism, and Buddhism and Jainism had arisen, proclaiming social orders unlinked to heredity. Early political consolidations gave rise to the loose-knit Maurya and Gupta Empires based in the Ganges Basin. Their collective era was suffused with wide-ranging creativity, but also marked by the declining status of women, and the incorporation of untouchability into an organised system of belief.[g] In South India, the Middle kingdoms exported Dravidian-languages scripts and religious cultures to the kingdoms of Southeast Asia.
In the early medieval era, Christianity, Islam, Judaism, and Zoroastrianism became established on India's southern and western coasts. Muslim armies from Central Asia intermittently overran India's northern plains, eventually founding the Delhi Sultanate, and drawing northern India into the cosmopolitan networks of medieval Islam. In the 15th century, the Vijayanagara Empire created a long-lasting composite Hindu culture in south India. In the Punjab, Sikhism emerged, rejecting institutionalised religion. The Mughal Empire, in 1526, ushered in two centuries of relative peace, leaving a legacy of luminous architecture.[h] Gradually expanding rule of the British East India Company followed, turning India into a colonial economy, but also consolidating its sovereignty. British Crown rule began in 1858. The rights promised to Indians were granted slowly, but technological changes were introduced, and modern ideas of education and the public life took root. A pioneering and influential nationalist movement emerged, which was noted for nonviolent resistance and became the major factor in ending British rule. In 1947 the British Indian Empire was partitioned into two independent dominions, a Hindu-majority Dominion of India and a Muslim-majority Dominion of Pakistan, amid large-scale loss of life and an unprecedented migration.
India has been a federal republic since 1950, governed through a democratic parliamentary system. It is a pluralistic, multilingual and multi-ethnic society. India's population grew from 361 million in 1951 to 1.211 billion in 2011. During the same time, its nominal per capita income increased from US$64 annually to US$1,498, and its literacy rate from 16.6% to 74%. From being a comparatively destitute country in 1951, India has become a fast-growing major economy and a hub for information technology services, with an expanding middle class. It has a space programme which includes several planned or completed extraterrestrial missions. Indian movies, music, and spiritual teachings play an increasing role in global culture. India has substantially reduced its rate of poverty, though at the cost of increasing economic inequality. India is a nuclear-weapon state, which ranks high in military expenditure. It has disputes over Kashmir with its neighbours, Pakistan and China, unresolved since the mid-20th century. Among the socio-economic challenges India faces are gender inequality, child malnutrition, and rising levels of air pollution. India's land is megadiverse, with four biodiversity hotspots. Its forest cover comprises 21.7% of its area. India's wildlife, which has traditionally been viewed with tolerance in India's culture, is supported among these forests, and elsewhere, in protected habitats.