New Mexico is a state in the Southwestern region of the United States of America; its capital is Santa Fe, which was founded in 1610 as capital of Nuevo México (itself established as a province of New Spain in 1598), while its largest city is Albuquerque with its accompanying metropolitan area. It is one of the Mountain States and shares the Four Corners region with Utah, Colorado, and Arizona. New Mexico is also bordered by the state of Texas to the east-southeast, Oklahoma to the northeast, and the Mexican states of Chihuahua to the south and Sonora to the southwest. With an estimated population of 2,096,829 as of the July 1, 2019, U.S. Census Bureau estimate, New Mexico is the 36th largest state by population. With a total area of 121,590 sq mi (314,900 km2), it is the fifth-largest and sixth-least densely populated of the 50 states. Due to their geographic locations, northern and eastern New Mexico exhibit a colder, alpine climate, while western and southern New Mexico exhibit a warmer, arid climate.
With a total area of 121,590 square miles (314,900 km2), New Mexico is the fifth-largest state. New Mexico's eastern border lies along 103°W longitude with the state of Oklahoma, and (due to a 19th-century surveying error) 2.2 miles (3.5 kilometres) west of 103°W longitude with Texas. On the southern border, Texas makes up the eastern two-thirds, while the Mexican states of Chihuahua and Sonora make up the western third, with Chihuahua making up about 90% of that. The western border with Arizona runs along the 109° 03'W longitude. The southwestern corner of the state is known as the Bootheel. The 37°N parallel forms the northern boundary with Colorado. The states of New Mexico, Colorado, Arizona, and Utah come together at the Four Corners in New Mexico's northwestern corner. Its surface water area is about 292 square miles (760 km2).
The New Mexican landscape ranges from wide, rose-colored deserts to broken mesas to high, snow-capped peaks. Despite New Mexico's arid image, heavily forested mountain wildernesses cover a significant portion of the state, especially towards the north. The Sangre de Cristo Mountains, the southernmost part of the Rocky Mountains, run roughly north–south along the east side of the Rio Grande in the rugged, pastoral north. The most important of New Mexico's rivers are the Rio Grande, Pecos, Canadian, San Juan, and Gila. The Rio Grande is tied for the fourth-longest river in the United States.