Before 1846, the entire region was part of Mexico, known as Alta California. Two treaties between Mexico and the United States brought a substantial portion of the Sonoran Desert under the United States’ control.
The Treaty of Guadalupe Hidalgo in 1848, the result of the war with Mexico, transferred significant parts of what is now California, Arizona, Nevada, New Mexico, Utah to the United States. The Gadsden Purchase of 1853 provided a small Mexican territorial segment to the United States, which added to the landmass that would someday become the States of Arizona and New Mexico.
Due to the bi-seasonal rainfall and subtropical warmth in the winter, the Sonoran Desert provides an environment for a plethora of flora and fauna. The Saguaro Cactus, the tall sentinels of this desert, are unique to this area and few other places. Various cacti provide food for fauna, including birds and desert mammals.
The Sonoran Desert is home to over seventeen Naïve American tribes. Mexican settlers wandered into the area seeking gold and silver. Soon, their families immigrated to the region. Conflicts between Indians and Mexican miners and their families were continual bloody affairs.
Anglos ventured into the region in the 1840s seeking adventure and opportunities to trap beaver. After 1854, Anglo migration increased substantially to Tucson and Tubac, villages located in the area.
Life in that part of the world was not luxurious. This region is a harsh place. The heat was intense during the summer. The Indian depredations regarding the intertribal conflict and hatred for Hispanics and Anglos interlopers were constant. Everyone fought each other for a piece of the pie.
Mining has always been very productive in the Sonoran Desert. Gold, silver, and particularly copper are plentiful resources in the region.
My newest novel, Taken At The Flood, is about life in that region in the mid to late nineteenth century. I think you will enjoy the story. Taken At The Flood is the second in the McBride series. The book is available through Amazon, Barnes and Nobel, Bookbaby, and other fine books purveyors.