The United States of America—usually referred to as the United States, the U.S., or America—is a constitutional federal republic comprising fifty states and a federal district. The country is situated mostly in central North America, where its forty-eight contiguous states and Washington, D.C., the capital district, lie between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south. The state of Alaska is in the northwest of the continent, with Canada to its east and Russia to the west across the Bering Strait, and the state of Hawaii is an archipelago in the mid-Pacific. The country also possesses several territories, or insular areas, scattered around the Caribbean and Pacific.
At 3.79 million square miles (9.83 million km²) and with more than 300 million people, the United States is the third or fourth largest country by total area, and third largest by land area and by population. The United States is one of the world's most ethnically diverse nations, the product of large-scale immigration from many countries.[7] The U.S. economy is the largest national economy in the world, with a nominal 2006 gross domestic product (GDP) of more than US$13 trillion (over 25% of the world total based on nominal GDP and almost 20% by purchasing power parity).[4][8]
The nation was founded by thirteen colonies of Great Britain located along the Atlantic seaboard. On July 4, 1776, they jointly issued the Declaration of Independence, which proclaimed their independence from Great Britain and their formation of a cooperative union. The rebellious states defeated Great Britain in the American Revolutionary War, the first successful colonial war of independence.[9] A federal convention adopted the current United States Constitution on September 17, 1787; its ratification the following year made the states part of a single republic with a strong central government. The Bill of Rights, comprising ten constitutional amendments guaranteeing many fundamental civil rights and freedoms, was ratified in 1791.
In the nineteenth century, the United States acquired land from France, Spain, the United Kingdom, Mexico, and Russia, and annexed the Republic of Texas and the Republic of Hawaii. Disputes between the agrarian South and industrial North over states' rights and the expansion of the institution of slavery provoked the American Civil War of the 1860s. The North's victory prevented a permanent split of the country and led to the end of legal slavery in the United States. The Spanish-American War and World War I confirmed the nation's status as a military power. In 1945, the United States emerged from World War II as the first country with nuclear weapons, a permanent member of the United Nations Security Council, and a founding member of NATO. In the post–Cold War era, the United States is the only remaining superpower—accounting for approximately 50% of global military spending—and a dominant economic, political, and cultural force in the world.
History
Native Americans and European settlers
The indigenous peoples of the U.S. mainland, including Alaska Natives, are thought to have migrated from Asia. They began arriving at least 12,000 and as many as 40,000 years ago.[26] Several indigenous communities in the pre-Columbian era developed advanced agriculture, grand architecture, and state-level societies. In 1492, Genoese explorer Christopher Columbus, under contract to the Spanish crown, reached several Caribbean islands, making first contact with the indigenous population. In the years that followed, the majority of the indigenous American peoples were killed by epidemics of Eurasian diseases.[27]
On April 2, 1513, Spanish conquistador Juan Ponce de León landed on what he called "La Florida"—the first documented European arrival on what would become the U.S. mainland. Of the colonies Spain established in the region, only St. Augustine, founded in 1565, remains. Later Spanish settlements in the present-day southwestern United States drew thousands through Mexico. French fur traders established outposts of New France around the Great Lakes; France eventually claimed much of the North American interior as far south as the Gulf of Mexico. The first successful English settlements were the Virginia Colony in Jamestown in 1607 and the Pilgrims' Plymouth Colony in 1620. The 1628 chartering of the Massachusetts Bay Colony resulted in a wave of migration; by 1634, New England had been settled by some 10,000 Puritans. Between the late 1610s and the American Revolution, an estimated 50,000 convicts were shipped to England's, and later Great Britain's, American colonies.[28] Beginning in 1614, the Dutch established settlements along the lower Hudson River, including New Amsterdam on Manhattan Island. The small settlement of New Sweden, founded along the Delaware River in 1638, was taken over by the Dutch in 1655.
By 1674, English forces had won the former Dutch colonies in the Anglo–Dutch Wars; the province of New Netherland was renamed New York. Many new immigrants, especially to the South, were indentured servants—some two-thirds of all Virginia immigrants between 1630 and 1680.[29] By the turn of the century, African slaves were becoming the primary source of bonded labor. With the 1729 division of the Carolinas and the 1732 colonization of Georgia, the thirteen British colonies that would become the United States of America were established. All had active local and colonial governments with elections open to most free men, with a growing devotion to the ancient rights of Englishmen and a sense of self government that stimulated support for republicanism. All had legalized the African slave trade. With high birth rates, low death rates, and steady immigration, the colonies doubled in population every twenty-five years. The Christian revivalist movement of the 1730s and 1740s known as the Great Awakening fueled interest in both religion and religious liberty. In the French and Indian War, British forces seized Canada from the French, but the francophone population remained politically isolated from the southern colonies. By 1770, those thirteen colonies had an increasingly Anglicized population of three million, approximately half that of Britain. Though subject to British taxation, they were given no representation in the Parliament of Great Britain.
