Most of the Mono Craters, which make up the bulk of the northern part of the Mono–Inyo chain, are phreatic (steam explosion) volcanoes that have since been either plugged or over-topped by rhyolite domes and lava flows.

Eruptions along the narrow fissure system under the chain began in the west moat of Long Valley Caldera 400,000 to 60,000 years ago.

The Mono–Inyo Craters form a volcanic chain in Eastern California that sits along a narrow north–south-trending fissure system extending from the north shore of Mono Lake through the western Long Valley Caldera, south of Mammoth Mountain.

[8]: 290 South of the Inyo volcanic chain are other features related to the dike system responsible for creating the craters, volcanoes and lava flows.

[17] Mule deer, coyotes, black bears, yellow-bellied marmots, raccoons and mountain lions all have ranges that are coincident with forests that cover parts of the Mono–Inyo craters.

Its structure is twofold; an outer tuff ring (forming a classic crater) and an inner plug, or dome of rhyolite, pumice and obsidian created from lavas.

[19]: 137  In this case, heat from the magma feeding Panum flashed groundwater to steam to create the tuff ring before lava reached the surface.

[8]: 291  Devil's Punch Bowl, located south of the main dome complex, stopped forming at an earlier stage of development.

[8]: 294  Once the flow stopped, it formed steep sided tongues of sharp and angular rock that are typically 200 to 300 feet (60 to 90 m) thick and have scree piles along their base.

[8]: 294–295  South Coulee originates from the crest of the Mono Domes, about 3 miles (5 km) from the southern end, flows down its east and west flanks and terminates at its foot.

[8]: 295 The Mono–Inyo chain of craters lies in east-central California, roughly parallel to the eastern escarpment of the Sierra Nevada mountain range.

[20]: 21–22  In the Long Valley region, where the craters are located, basin and range extension encroaches onto the thick and stable crust of the Sierra Nevada.

Eruptions of basalt and andesite 400,000 to 60,000 years ago in the west moat of Long Valley Caldera were the first activity associated with the Mono–Inyo Craters system.

[26][27]: 231  About 660 feet (200 m) of subsidence has occurred within a ring fracture system centered on Pumice Valley west of the chamber in the last 700,000 years.

[27]: 231,  [28]: 55,  [29] Repeated eruption of dacite and rhyodacite from vents on the southwest rim of the caldera from 220,000 to 50,000 years ago formed Mammoth Mountain, a volcano composed of overlapping lava domes.

[31][32] A vertical sheet-like mass of magma, called a dike, caused groundwater to explosively flash to steam, creating a line of vents 4 miles (6 km) long.

[33]: 67  A mix of ash and pulverized rock, called tephra, covered about 3,000 square miles (8,000 km2) of the Mono Lake region.

[34][36] Pumice and ash covered an extensive area downwind, and about 1 inch (2.5 cm) of tephra was deposited where the town of Mammoth Lakes, California, now sits.

Exposed rhyolite is on the north part of the island, and a group of seven dacite cinder cones and a lava flow are on the northeastern corner.

[38] Unworked obsidian was carried by the Mono Paiutes over passes in the Sierra Nevada to trade with other Native American groups.

[8]: 296  Excavation of an 11.5-mile (18.5 km) water tunnel under the southern part of the Mono Craters dome complex started in 1934 and was completed in 1941.

[22]: 51  Water diverted from its natural outlet in Mono Lake passes through the tunnel on its way to the Los Angeles Aqueduct system.

Hot deserts bounded by snow-laden mountains,—cinders and ashes scattered on glacier-polished pavements,—frost and fire working together in the making of beauty.

They are exceptional features in the scenery of the region, and are rendered all the more striking by their proximity to the angular peaks and rugged outlines of the High Sierra.

[46] The Long Valley to Mono Lake region is one of three areas in California that are in the United States Geological Survey's volcanic hazards program.

Steam blast eruptions under a lake could form large waves capable of flooding nearby areas and starting mudflows.

A bookstore, an information desk staffed by USDA Forest Service Rangers, and museum exhibits help to orient visitors.

[44] The Mono Lake Committee has a staffed office and visitor information center in Lee Vining on the corner of U.S. Route 395 and 3rd Street.

California State Route 120 approaches the northern and eastern parts of the Mono Domes, including Panum Crater.

[54] The summit of Mammoth Mountain provides panoramic views of the craters and domes of the Mono–Inyo volcanic chain, Mono Lake, the Sierra Nevada and Long Valley Caldera.