Katanuma Pond (潟沼) is a crater lake located in Naruko, Miyagi pref.　It is one of the strongest acid water lake in the world. Therefore, there is no living organism in this lake. The color of the lake is a beautiful green. It is 1.3km around, 16m deep. It was created by the volcanic activity in 1100 years ago.

Tourist Info.
There are parking, restroom and restaurant.

Access
0. at Kogota Station.
1. use JR Rikuu Line to Naruko Onsen (1hr. 18min.)
2. walk south (1hr.)