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 who followed the voyages of Christopher Columbus starting in 1492. The largest settlements were by the English on the East Coast, starting in 1607. By the 1770s the Thirteen Colonies contained two and half million people, were prosperous, and had developed their own political and legal systems. The British governments threat to American self-government led to war in 1775 and the Declaration of Independence in 1776. With major military and financial support from France, the patriots won the American Revolution. In 1789 the Constitution became the basis for the United States federal government, with war hero George Washington as the first president. 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 national government was much stronger, and it now had the explicit duty to protect individuals. The present 48 contiguous states were admitted by early 1912, with Alaska and Hawaii added in 1959.
Thanks to an outburst of entrepreneurship in the North and the arrival of millions of immigrant workers from Europe, the U.S. became the leading industrialized power by the early 20th century. Disgust with corruption, waste, and traditional politics stimulated the Progressive movement, 1890s-1920s, which pushed for reform in industry and politics and put into the Constitution womens suffrage and Prohibition of alcohol (the latter repealed in 1933).