Mexico, officially the United Mexican States, is a country in the southern portion of North America. Covering 1,972,550 km2, it is the world's 13th largest country by area; with a population of almost 130 million, it is the 10th most populous country and has the most Spanish speakers in the world. Mexico is a constitutional republic comprising 31 states and Mexico City, its capital and largest city, which is among the world's most populous metropolitan areas.