State, southwestern U.S. Area: 113,999 sq mi (295,256 sq km). Pop. (2009 est.): 6,595,778. Capital: Phoenix. Arizona is bordered by Mexico and the U.S. states of Utah, New Mexico, California, and Nevada. The highest point is Humphreys Peak, at 12,633 ft (3,850 m). The site of Grand Canyon and Petrified Forest national parks, Arizona also contains much of America's Indian tribal lands. Humans settled the area more than 25,000 years ago. Nomadic Apache and Navajo Indians arrived after the collapse of the Ancestral Pueblo (Anasazi) and Hohokam civilizations. They were followed in the 16th century by Spanish treasure seekers from Mexico, including Francisco Vázquez de Coronado, establishing Mexico's claim to the area. In 1776 the Mexican army built a presidio at Tucson. After the Mexican War, Arizona was ceded to the U.S. as part of New Mexico in 1848; the Gadsden Purchase added to it in 1853. Organized as a territory in 1863, Arizona became the 48th state in 1912. Though still lightly populated, it has grown rapidly in population in recent decades, largely because of its climate. About one-fifth of the population is Spanish-speaking, while about 5% is American Indian, including Navajo, Hopi, Apache, Papago, and Pima. Its diverse economy includes agriculture, mining, aerospace, electronics, and tourism.