It is situated at the southwest of Myōkō city, Niigata Prefecture, and a part of Jōshin'etsu-kōgen National Park.

Mount Myōkō was formed beginning about 300,000 years ago, in a series of eruptions producing a broad spectrum of lava types including basalt, andesite, and dacite.

Around 19,000 years ago, the top was blown off in a major eruption, forming a 3 km (2 mi) wide caldera.

The heavy cruiser Myōkō of the Imperial Japanese Navy and an Aegis destroyer of the Japan Maritime Self-Defense Force are named after this mountain.

In 1990 the Nippon Jamboree, a camping festival, was held on the Myōkō plateau (妙高高原, myōkōkōgen) during which the participants climbed the mountain.