Myojin Pond is located at the eastern base of Mt. Kasa. Mt. Kasa is a small volcano 112 meters in height that was formed by an eruption roughly 10,000 years ago. When a sandbar formed to connect Mt. Kasa with the mainland, the part that didn’t get filled in became Myojin Pond.

The pond is connected to the open sea through gaps in the lava boulders, and the water level changes according to the ebb and flow of the ocean. The pond is home to a variety of saltwater fish whose population originates from fish released there by local fishermen during rituals of prayer for safety and bountiful catches. The pond is known as a natural aquarium, and people standing around the pond can view the fish in it. It has been registered as a national natural treasure.