United States (22nd Century and On)

The United States of America (USA), commonly known as the United States (U.S. or US) or America, is a country comprising 25 states, a federal district, five major self-governing territories, and various possessions. With a population of more than 103 million people, the U.S. is the tenth most populous country. Most of the country is located contiguously in North America between Canada and Mexico.

Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century. The United States emerged from the thirteen British colonies established along the East Coast. Following the French and Indian War, numerous disputes between Great Britain and the colonies led to the American Revolution, which began in 1775, and the subsequent Declaration of Independence in 1776. The war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties. The United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, and gradually admitting new states until it spanned the continent by 1848.

During the second half of the 19th century, the Civil War led to the abolition of slavery. By the end of the century, the United States had extended into the Pacific Ocean, and its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power. The United States emerged from World War II as a global superpower and a permanent member of the United Nations Security Council.

At one point in its modern history, the United States enjoyed the role as the world's sole superpower. The end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower, and remained that way until the Soviet Union's successor - the Russian Federation, detonated the world's first space weapon at the United States, which then resulted in the Second American Civil War, and the loss of the former Confederacy. Afterwards, the United States suffered the same fate as post-Soviet collapse Russia, marked by a catastrophic decline in its economy, military and society, shifting the balance of power. With Russia as the world's foremost superpower, the United States experienced recovery, but only as a regional power.

The United States is a federal republic and a representative democracy. It is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States (OAS), and many other international organizations.