What year is USA born?

Excuse me, but I believe there's a bit of a misunderstanding in the question. The United States of America, or USA for short, is not a person or an entity that can be said to have been "born" in a specific year. Instead, it's a country that was formed through a series of historical events, treaties, and declarations. If you're asking about the year when the United States declared its independence from Great Britain, that would be July 4, 1776, when the Continental Congress adopted the Declaration of Independence. However, the United States didn't officially become a country until the Treaty of Paris was signed in 1783, which formally recognized the independence of the United States and ended the American Revolutionary War. So, to answer your question in the spirit it was intended, the United States of America was not "born" in a specific year, but rather, it emerged as a nation through a series of historical events and declarations over several years.