General presentation of the United States of America

Foreword

The United States of America — also referred to as the United States, the USA, the U.S., America, or the States — is a federal republic of 50 states located primarily in central North America. The United States proper has land borders with Canada and Mexico, as well as several territorial water boundaries with Canada, Russia and The Bahamas. It is otherwise bounded by the Pacific Ocean, the Bering Sea, the Arctic Ocean, and the Atlantic Ocean. Two of the 50 states, Alaska and Hawaii, are not contiguous with any of the other states. The United States also has a collection of overseas territories and possessions around the world. Each of the 50 states has a high level of local autonomy under the system of federalism.

The United States traces its national origin to the United Colonies of America governed by the Second Continental Congress formed in 1775 and the Declaration of Independence by the thirteen British colonies in 1776 that they were free and independent states. They were recognized as such by the Treaty of Paris (1783). Since the mid-20th century, it has become a dominant influence in contemporary economic, political, military, scientific, technological and cultural matters.

The United States was founded under a tradition of government based on the consent of the governed under the representative democracy model. The particular form of government of the United States, called (presidential-congressional), has since been adopted by many other countries, mostly in Central America and South America.

History

Following the European colonization of the Americas, thirteen colonies split from Britain and formed the United States, the world's first constitutional federalist republic, after their Declaration of Independence in 1776 and the Revolutionary War (1775–1783). The original political structure was a confederation in 1777, ratified in 1781 as the Articles of Confederation.

After long debate, this was supplanted by the Constitution in 1789, forming a more centralized federal government. Prior to all these was the Albany Congress in 1754, in which a union was first seriously proposed.

During the 19th century, many new states were added to the original thirteen as the nation expanded across the North American continent, destroying and resettling many Indian nations in a decades-long military campaign. Through coercion, military prowess, and diplomatic leverage, it acquired a number of overseas possessions, from Cuba to the Philippines, though it lost many of these over time. See also United States territorial acquisitions.

During this period the nation also became an industrial power. This continued into the 20th century, which some have termed "the American Century" due to America's tremendous influence on the world.