The ancestor's of the American Indians were among the first people to set foot in the Americas 30,000 years ago. They have lived in the Sonoran Desert near the Gila River in what is now Sonoita, AZ for at least 2,000 years. Called the Pima Indians by exploring Spaniards who first encountered them in the 1600s, these early Americans called themselves "O'Odham," the River people, and those with whom they intermarried, "Tohono O'Odham," the Desert people.
The plant and animal communities, and
landscape-shaping processes in southern Arizona
have not always been the same. Geological and biological
records of environmental changes include floodplain sediments, lake and playa deposits, dune formations, mammal remains, insect fossils, pollen sequences, and the plant
remains preserved in packrat middens.
Ranching began in Arizona with the arrival of Spanish conquistadors, who introduced cattle to southern Arizona and designated vast land grant haciendas like the Arivaca, Reventon, Sopori and Canoa along the Santa Cruz River and the San Bernardino in the southeast corner of the state. The Spanish also left the remnants of their language to describe the cattle and cowboying experience, a blend of Spanish-Mexican words including lariat, corral, remuda and bronco.
Pimería Alta (upper land of the Pimas) was a province or region referred as Spanish Colonial Mexico encompassing what is now southern Arizona and northern Sonora. The area took its name from the Pima and closely related O'odham (Papago) indigenous peoples residing in the Sonoran Desert. Pimería Alta was the site of the Spanish missions in the Sonoran Desert established by Father Kino in the late 17th century.