Little Walker Caldera is a depression in the eastern Sierra Nevada in California that is adjacent to the Sweetwater Mountains.
Andesitic lava and tuff from the series of three eruptive events are found several hundred feet thick as far away as Antelope Valley, Mono County, 20 miles (32 km) north, Bridgeport Valley to the south, and Sonora 60 miles (97 km) to the west.
[1] The lava flows near Sonora are readily visible from California State Route 108 and followed the gold-laden stream beds in the area.
Rich placer gold deposits have been revealed by excavating the ancient stream beds that lie underneath the lava flows.
The Little Walker Caldera is classified as extinct, although it continues to produce substantial hot spring activity and occasional earthquakes.