A mile-long 300-foot high lava dome made up of shiny black volcanic glass that is part of the Mono–Inyo Craters volcanic chain located in the Inyo National Forest.
Obsidian is one of the sharpest natural materials known to man and have played a significant role in the evolution of homo-sapiens’ tool-making ability.
The eruptions that formed each of these lava domes 550-600 years ago began with an explosive phase, then exuded slow-moving, sticky lava which oozed to the surface and cooled too quickly to allow crystal formation.
To get to Obsidian Dome, drive 10.4 miles north on Highway 395 from its intersection with Devil’s Postpile/ Mammoth Lakes Exit to a dirt road called by at least two names, Glass Flow Road and Obsidian Dome Road. Drive about one mile to a fork on the road with a sign directing you to Obsidian Dome. Another .3 miles up this road to a large parking area. You may drive another .3 miles to a secondary parking area with a gate. Driving to this secondary parking possibility is not recommended for low clearance vehicles.