The United States is the world's fifth or sixth-largest country by total area.
Mexico . Covering almost two million square kilometers ( over 760,000 sq mi ) , Mexico is the sixth largest country in the Americas by total area and the 13th largest independent nation in the world . United States . At 3.8 million square miles ( 9.8 million km2 ) and with over 324 million people , the United States is the world 's third - or fourth-largest country by total area , third-largest by land area , and the third-most populous .