The United States of America usually referred as the United States or U.S., is a federal constitutional republic encompassing fifty states and a federal district. The United States of America comprises mainly the North American continent between Canada and Mexico. At 3.79 million square miles (9.83 million km2) and with reference to 306 million common populations, the United States is the third or fourth largest country by total area and third largest by land area and by population. The United States is one of the world's most culturally diverse and multicultural nations, the product of large-scale immigration from many countries.

The United States of America generally recognised as the United States, the U.S., the USA, or America, is a central constitutional republic encompassing fifty states and a federal district. On July 4, 1776, they issued the Declaration of Independence, which declares their sovereignty from Great Britain and their formation of a cooperative union. The rebellious states conquered Great Britain in the American Activist War, the first successful colonial war of independence. At present, United States has significance both as a financial supplier and a steadfast partner in the effort to achieve the overarching mission of poverty reduction in developing countries.