Archeological evidence is inconclusive on the origins of the Upper Pima/Pima-Papago. It is not clear if they are the descendants of the Hohokam or of some other pre-European culture such as the Mogollon. In early post-European times, they bordered various Apache tribes to the east; the Opata, Lower Pima, and Seri to the south; the Cocopa, Quechan (or Yuma), and Maricopa to the west; and the Yavapai to the north. In the premodern period, relations with the Apache, Quechan, and Yavapai were warlike, those with the Cocopa and Maricopa were peaceful, and those with other peoples were ruled by the Pax Hispanica.
The periods of post-European history are scant European contact (c. 1550-1700), premodern (1700-1900), and modern (1900-the present). Contact began soon after Columbus, but Spanish mission and secular (military, ranching, mining) settlement did not enter Upper Pima territory until nearly 1700. Throughout the premodern period those settlements, whether Spanish, Mexican, or European-American, remained sparse and remote from centers of White culture. For their part, the Upper Pima/Pima-Papago tended to accept European-Americanization whenever it was offered. In premodern times they fought for Spain, Mexico, and the United States against Apaches and Yavapais. When the United States entered and brought peace to the region, from 1850 to 1880, ushering in the modern period, the economic pace quickened on both sides of the new U.S.-Mexican border that divided Pima-Papago territory. These post-1850 developments did not cost the Pima-Papago much additional territory. Except for a town-studded railroad swath that also passed through their territory, separating the Gila River Pirnas from the Papagos, the new non-Indian settlements were on land that had earlier been ceded to Spain, Mexico, Yavapais, or Apaches. The unceded Pima-Papago territory (except for the most arid western extremity of it, the home of the Sand Papagos) was incorporated into Indian reservations between 1875 and 1925. From the largest in territory to the smallest, the reservations are Sells, Gila River, San Xavier, Salt River, Ak Chin, and Gila Bend.