The United States of America is a nation state located on the planet Earth.The nation was founded by thirteen colonies of Britain located along the Atlantic seaboard. On July 4, 1776, they issued the Declaration of Independence, which proclaimed their independence from Great Britain and their formation of a cooperative union. The capital city is Washington D.C. which is home to the President of the United States.
Kryptonian refuge Kal-El landed in the United States of America. He was recovered by two Americans known as Martha and Jonathan Kent outside the town of Smallville, Kansas. The couple adopted him and raised him at the home on the Kent Farm. He was renamed Clark Kent and brought up to become "Superman", who fought for "Truth, Justice and the American Way!"
In Action Comics #900 after an incident in the Middle East caused him to renounce his American citizenship at the United Nations to continue working as a superhero for Earth not just one nation and their interests.