Identification. The Pima Bajo, or Lower Pima of northern Mexico, are related to other Piman-speaking groups living in southern Arizona. These latter groups were referred to by Spaniards as the "Pimeria Alta" and today consist of various groups in southern Arizona and a small group living across the border in northern Mexico. The lowland Pima identify themselves as 'O'Odham (people, tribesman, person, human) and the highland, or Mountain Pima as Taramil 'O'Odham (Tarahumara-like people). The highland Pima refer to themselves as Òob and to the lowland groups as Ó Odham. Spanish missionaries called them all "Pima," after the indigenous term for "nothing" or "I don't know."
Location. The Pima Bajo were situated aboriginally in their current location, and in a larger territory in eastcentral Sonora and the adjacent areas in western Chihuahua. They were split into two groups: the lowland, desert branch of central Sonora, consisting of the Névomes living on both sides of the middle Río Yaqui and the Ures located near the confluence of the Sonora and San Miguel rivers, and the highland branch, the Yécora of the Sierra Madre Occidental in and around the towns of Yécora and the Tutuaca between the headwaters of the Papagochi, Tutuaca, and Mayo rivers near the Sonora-Chihuahua border. Today the Névome may be extinct, whereas the Ures group is rapidly acquiring the social and material traits of the local non-Indian population.
Demography. At the end of the seventeenth century, the Pima Bajo population was estimated at less than 6,000 and that of the Mountain Pima at less than 2,000. During the nineteenth century, the Pima Bajo experienced an abrupt decline in numbers. Disease and warfare did not decrease their numbers as they had in other cases of Spanish contact, but an ever-increasing number of Spaniards and mestizos displaced them from their native soil. In the early 1990s the best estimates of the lowland Pima Bajo population were about 200 and, of the highland Pima Bajo, between 1,500 and 2,000 persons, with some estimates ranging as high as 4,000. Population size is difficult to estimate accurately because the Pima Bajo live in small scattered clusters and migrate in search of temporary work in surrounding mines, mills, and lowland towns for work in agriculture.
Linguistic Affiliation. The Pima Bajo language is part of the Northern Branch, or Tepiman, of the Uto-Aztecan languages; thus, the Pima Bajo are grouped linguistically with the Tepehuan of Durango and southern Chihuahua and the Northern Piman speakers in Arizona. Lowland and Highland Piman are related languages, and each is characterized by two dialects. One of the lowland dialects is now extinct. The other lowland dialect is similar to the Pima Alta language spoken by the Papago, now called the Tohono O'Otam.