The Republic of New America, often shortened as New America or abbreviated as the R.N.A. or N.A., is a semi-presidential federal republic composed of 40 states, three major-self governing territories, one autonomous region, and various smaller possessions. At over one million square miles (2.6 million sq km), New America is the sixth-or-seventh-largest nation in the world by total area, and with a population of approximately 204 million, is the world's fifth-most populous nation. Much of this population is located in major cities, such as New York, the most populous city, and Washington, the capital. The nation's extremely diverse geography and climate make it one of the world's mega-diverse countries.
Paleo-Indians migrated from Siberia to mainland North America via the Bering land bridge at least 15,000 years ago, and scattered around the continent, with various tribes each having their own culture, history, and politics. European colonization of the Americas began in the 16th century. The United States emerged from thirteen British colonies on the North American east coast following the American Revolutionary War, which began in 1775 and ended in 1783. The nation rapidly expanded across the continent, becoming a great power following the Spanish-American War and World War I, and a superpower alongside the Soviet Union following the end of World War II in 1945. Following the end of the Cold War collapse of the Soviet Union in late 1991, the nation was considered the world's only superpower until the late 2020s, when China was recognized as a global superpower, as were other nations, such as India, Nigeria, Brazil, Argentina, Mexico, and Indonesia over the next several decades.
In 2076, the Great Nuclear War decimated major cities in the United States and across the world, and society lived on in scattered "survivor populations", many of which assembled in rural and suburban areas that were not as impacted by dangerous levels of radiation as the larger cities. These survivor states conflicted, shifted, and united over the course of several decades, and a group of these states in the former northeastern United States reformed into an entity known as New America in the late 2140s. As this new nation expanded, it contacted more survivor states, absorbing the majority of them until it controlled virtually all of the former eastern United States by the advent of the 2180s. The new nation rapidly rose to the status of a great power, and is considered a sort of superpower to this day.
New America is one of the world's oldest surviving federations. It is a founding member of many important international organizations, such as the League of Nations, First Bank, American Union, and others. It is a very highly developed nation, with the world's tenth-largest economy by nominal GDP and twelfth-largest by PPP, accounting for much of the GDP of both North America and the world as a whole.
In 1507, German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of Amerigo Vespucci, an Italian explorer and cartographer. The first documentary evidence of the name "United States of America" being used is in a letter dated January 2, 1776, written by Stephen Moylan and addressed to Lt. Col. Joseph Reed.
Following the creation of the Articles of Confederation, the initial American constitution, the name "United States of America" became widespread among the American public, and eventually, in other nations across the planet. The name continued to be used for several hundred years, along with the shortened names "United States" and "America", along with the abbreviations "U.S.", and "U.S.A". The demonym of a citizen of the country was an "American", which is still occasionally used in the present day.
After the collapse of the United States, citizens were referred to by the demonyms of the survivor states or communities that they were members of. In 2148, the Republic of New America was consolidated, following a convention in the future capital of Washington - the former capital of the United States. The nation is often shortened as "New America", while the abbreviations "R.N.A." and "N.A." are occasionally used. The demonym of a citizen of the country is "New American", although some sources still occasionally refer to citizens as "Americans", in reference to the former United States.