Unlike other agricultural peoples of the Southwest, the Navajo have never been town dwellers. In the late prehistoric and early historic periods they lived in small encampments clustered within a fairly restricted area in northwestern New Mexico. Later, increasing warfare with the Spanish forced them to adopt a more mobile existence, and bands of Navajo might range over hundreds of miles between the Rio Grande and the Colorado River. Since their pacification in the 1860s, the Navajo have lived in extended-family encampments, Usually numbering from two to four individual households, that are scattered over the length and breadth of the vast Navajo Reservation. Many extended families maintain two residential encampments a few miles apart. The summer camps are located close to maize fields and therefore are concentrated to some extent in the more arable parts of the reservation; the winter camps are more scattered and are located primarily for easy access to wood and water.