The history of the United States traditionally starts with the Declaration of Independence in the year 1776, yet its territory was occupied first by the Native Americans since prehistoric times and then also by European colonists mostly following the voyages of Christopher Columbus starting in 1492. The Thirteen Colonies declared independence from the British Empire during the American Revolution and as states ratified the Articles of Confederation. In 1789 the Constitution became the basis for the United States federal government. The young nation continued to struggle with the scope of central government and with European influence, creating the first political parties in the 1790s, and fighting a second war for independence in 1812.
U.S. territory expanded westward across the continent, brushing aside Native Americans and Mexico, and overcoming modernizers who wanted to deepen the economy rather than expand the geography. Slavery of Africans was abolished in the North, but heavy world demand for cotton let it flourish in the Southern states. The 1860 election of Abraham Lincoln calling for no more expansion of slavery triggered a crisis as eleven slave states seceded to found the Confederate States of America in 1861. The bloody American Civil War (1861–65) redefined the nation and remains the central iconic event. The South was defeated and, in the Reconstruction era, the U.S. ended slavery, extended rights to African Americans, and readmitted secessionist states with loyal governments. The present 48 contiguous states were admitted by early 1912.
The U.S. rose as an industrialized power by the early 20th century. Lifestyle changes led to the Progressive movement, which pushed for reform in industry and politics and is associated with women's suffrage and Prohibition of alcohol (the latter failed by 1933). Initially neutral in World War I, the U.S. eventually declared war on Germany in 1917, yet popular support for non-interventionism derailed post-war attempts to foster international cooperation. The Wall Street Crash of 1929 punctuated the onset of the Great Depression, to which the federal government responded with New Deal recovery programs. After the Japanese attack on Pearl Harbor in December 1941, the U.S. entered World War II alongside the Allies and helped defeat Nazi Germany in Europe and, with the detonation of newly-invented atomic bombs, Japan in Asia and the Pacific.
The Soviet Union and the U.S. emerged as opposing superpowers after the war and began the Cold War confronting indirectly in an arms race, the Space Race, and intervention in Europe and eastern Asia. Liberalism reflected in the civil rights movement and opposition to war in Vietnam peaked in the 1960s–70s before giving way to conservatism in the early 1980s. The Cold War ended when the Soviet Union dissolved in 1991, leaving the U.S. to prosper in the booming Information Age economy that was boosted, at least in part, by information technology. International conflict and economic uncertainty heightened by 2001 with the September 11 attacks and subsequent War on Terror and the late-2000s recession.
The first residents of what is now the United States emigrated from Asia over 30,000 years ago by crossing Beringia into present-day Alaska then headed south. Archaeological evidence of these people, the ancestors of the Native Americans, dates back to between 40,000 and 16,500 years ago.
The pre-Columbian era incorporates all period subdivisions in the history and prehistory of the Americas before the appearance of significant European influences on the American continents, spanning the time of the original settlement in the Upper Paleolithic period to European colonization during the Early Modern period. While technically referring to the era before Christopher Columbus' voyages of 1492 to 1504, in practice the term usually includes the history of American indigenous cultures until they were conquered or significantly influenced by Europeans, even if this happened decades or even centuries after Columbus' initial landing.
After a period of exploration by people from various European countries, Spanish, Dutch, English, French, Swedish, and Portuguese settlements were established. In the 16th century, Europeans brought horses, cattle, and hogs to the Americas and, in turn, took back to Europe maize, potatoes, tobacco, beans, and squash. The disease environment was very unhealthy for explorers and early settlers. The Native Americans became exposed to new diseases such as smallpox and measles and died in very large numbers, usually before large-scale European settlement began.
Spanish, Dutch, and French colonization
Spanish explorers were the first Europeans to arrive in what is now the United States with Christopher Columbus' second expedition, which reached Puerto Rico on November 19, 1493; others reached Florida in 1513. Quickly Spanish expeditions reached the Appalachian Mountains, the Mississippi River, the Grand Canyon and the Great Plains. In 1540, Hernando de Soto undertook an extensive exploration of the present U.S. and, in the same year, Francisco Vázquez de Coronado led 2,000 Spaniards and Native Mexican Americans across the modern Arizona–Mexico border and traveled as far as central Kansas. The Spanish sent some settlers, creating the first permanent European settlement in the continental United States at St. Augustine, Florida in 1565, but it was in such a harsh political environment that it attracted few settlers and never expanded. Much larger and more important Spanish settlements included Santa Fe, Albuquerque, San Antonio, Tucson, San Diego, Los Angeles and San Francisco. Most Spanish settlements were along the California coast or the Santa Fe River in New Mexico.
New Netherland was the 17th century Dutch colonial province on the eastern coast of North America. The Dutch claimed territory from the Delmarva Peninsula to Buzzards Bay, while their settlements concentrated on the Hudson River Valley, where they traded furs with the Native Americans to the north and were a barrier to Yankee expansion from New England. Their capital, New Amsterdam, was located at the southern tip of the island of Manhattan and was renamed New York when the English seized the colony in 1664. The Dutch were Calvinists who built the Reformed Church in America, but they were tolerant of other religions and cultures. The colony left an enduring legacy on American cultural and political life, including a secular broadmindedness and mercantile pragmatism in the city, a rural traditionalism in the countryside typified by the story of Rip Van Winkle, and politicians such as Martin Van Buren, Theodore Roosevelt, Franklin D. Roosevelt and Eleanor Roosevelt.
New France was the area colonized by France in North America during a period extending 1534 to 1763, when Britain and Spain took control. There were few permanent settlers outside Quebec, but fur traders ranged working with numerous Indian tribes who often became military allies in France's wars with Britain. The territory was divided into five colonies: Canada, Acadia, Hudson Bay, Newfoundland and Louisiana. After 1750 the Acadians—French settlers who had been expelled by the British from Acadia (Nova Scotia)—resettled in Louisiana, where they developed a distinctive rural Cajun culture that still exists. They became American citizens in 1803 with the Louisiana Purchase. Other French villages along the Mississippi and Illinois rivers were absorbed when the Americans started arriving after 1770.