New Mexico is a state located in the southwestern region of the United States. It is the 5th largest state at 121,589 square miles and the 36th most populated with just over 2 million residents. It was the 47th state to be admitted to the U.S. in 1912. Before that it was part of the Imperial Spanish viceroyalty of New Spain and also Mexico at one point. As a result of the Mexican-American War, it because part of U.S. territory.