The Mono Basin is an endorheic basin located East of Yosemite National Park in California, United States. It is bordered to the West by the Sierra Nevada, to the East by the Cowtrack Mountains, to the North by the Bodie Hills, and to the South by the North ridge of the Long Valley Caldera. Principal features of the Basin include Mono Lake, the Mono-Inyo Craters, the Aeolian Buttes, and the town of Lee Vining, CA.

Mono Lake is believed to have formed at least 760,000 years ago, dating back to the Long Valley eruption. Sediments located below the ash layer hint that Mono Lake could be a remnant of a larger and older lake that once covered a large part of Nevada and Utah, making it among the oldest lakes in North America. At its height during the last ice age, the lake may have been 900 feet (270 m) deep; prominent old shore lines, called strandlines by geologists, can be seen above Lee Vining (near the white "LV") and along volcanic hills northeast of the current lake.