The Navajo are a composite group with over 50 separate clans. In the 17th cent. they occupied the region between the San Juan and Little Colorado rivers in NE Arizona, but they ranged far outside that territory. The Navajo were a predatory tribe who (often in alliance with their relatives, the Apache) constantly raided the Pueblo and later the Spanish and Mexican settlements of New Mexico.
When the Americans occupied (c.1846) New Mexico, the Navajo pillaged them. Punitive expeditions against the Navajo were only temporarily successful until Kit Carson, by destroying the Navajo's sheep, subdued them in 1863–64. A majority of them were imprisoned for four years at Fort Sumner in New Mexico. In 1868 they were released from prison and given a reservation of 3.5 million acres (1,41,000 hectares) in NE Arizona, NW New Mexico, and SE Utah and a new supply of sheep. The Navajo then numbered some 9,000.
Since that date they have been steadily increasing in number. By 1990 the country's 225,000 Navajo constituted the second largest Native American group in the United States. Their reservation has grown to 16 million acres (6,475,000 hectares), today sustaining such enterprises as lumbering, mining, and farming. Navajo-owned enterprises are growing, including the largest Native American newspaper in the United States and Navajo Community College, the first Native American–operated college. The Navajo reservation surrounds the Hopi reservation in Arizona. This has resulted in numerous land disputes, and in the 1960s and 70s, Navajo expansion on lands set aside for joint use provoked court action and a partition of the disputed land. A 1992 federal court decision assigned most of the remaining disputed land to the Navajo. Some Navajo were permitted to remain on Hopi land under 75-year leases.