The United States is located in the middle of the North American continent, with Canada to the north and Mexico to the south. The United States ranges from the Atlantic Ocean on the nation's east coast to the Pacific Ocean bordering the west, and also includes the state of Hawaii, a series of islands located in the Pacific Ocean, the state of Alaska located in the northwestern part of the continent above the Yukon, and numerous other holdings and territories.

The first known inhabitants of modern-day United States territory are believed to have arrived over a period of several thousand years beginning sometime prior to 15,000 - 50,000 years ago by crossing Beringia into Alaska. 1 2 Solid evidence of these cultures settling in what would become the US is dated to at least 14,000 years ago.

Research has revealed much about the early settlers of North America as indicated by Cyrus Thomas.

In its beginnings, the United States consisted only of the Thirteen Colonies, which consisted of states occupying the same lands as when they were British colonies. American colonists fought off the British army in the American Revolutionary War of the 1770s and issued a Declaration of Independence in 1776. Seven years later, the signing of the Treaty of Paris officially recognized independence from Britain. In the nineteenth century, westward expansion of United States territory began, upon the belief of Manifest Destiny, in which the United States would occupy all the North American land east to west, from the Atlantic to the Pacific Oceans. By 1912, with the admission of Arizona to the Union, the U.S. reached that goal. The outlying states of Alaska and Hawaii were both admitted in 1959.

Ratified in 1788, the Constitution serves as the supreme American law in organizing the government; the Supreme Court is responsible for upholding Constitutional law. Many social progresses came up starting in the nineteenth century; those advancements have been widely reflected in the Constitution. Slavery was abolished in 1865 by the Thirteenth Amendment to the United States Constitution; the following Fourteenth and Fifteenth Amendments respectively guaranteed citizenship for all persons naturalized within U.S. territory and voting for people of all races. In later years, civil rights were extended to women and black Americans, following effective lobbying from social activists. The Nineteenth Amendment prohibited gender discrimination in voting rights; later, the Civil Rights Act of 1964 outlawed racial segregation in public places.

The Progressive Era marked a time of economic growth for the United States, advancing to the Roaring Twenties. However, the Wall Street Crash of 1929 led to the Great Depression, a time of economic downturn and mass unemployment. Consequently, the U.S. government established the New Deal, a series of reform programs that intended to assist those affected by the Depression. The New Deal has varied success. However, once the U.S. entered World War II in December 1941, the economy quickly recovered, so much that the U.S. became a world superpower by the dawn of the Cold War. During the Cold War, the U.S. and the Soviet Union were the world's two superpowers, but with the end of the Cold War and the collapse of the Soviet Union, United States became the world's only superpower.