 The California Gold Rush in the 1850s saw gradually increasing mining in Merced Canyon and Yosemite Valley . Many Native Americans in the area revolted , leading to conflicts between miners and the Ahwahnechee . In 1851 the Mariposa Battalion was formed to drive the remaining Ahwahnechee out of the valley into reservations . The Battalion fought an Ahwahnechee group led by Chief Tenaya over the South Fork of the Merced River . Eventually , they succeeded in driving most of the Indians out of the Yosemite Valley , first into a reservation near Fresno . Following the gold rush , the Ahwahnechee were allowed back into Yosemite Valley , but further incidents prompted a second battalion to drive them out , this time to the Mono Lake area . Many place names in the valley have their origin from the Mariposa Battalion . 
