The United States of America is a nation located in North America. It is a federal-constitutional republic, and is divided into ? states. From the west to the south, the United States shares land borders with Siberia and Central America. It also shares maritime borders with the Empire of Japan by the Sea of Okhotsk and Venezuela by the Caribbean Sea. At 24,596,353 sq km, the United States is the largest country in the world, covering more than one ninth of the Earth's inhabited land area. The United States is also the third-most populated nation on the planet, the first being China; and the second being India.