Ohsio Dam is an earthfill dam located in Gunma Prefecture in Japan.

The dam is used for flood control and irrigation.

The catchment area of the dam is 130.5 km2.

The dam impounds about 15 ha of land when full and can store 1841 thousand cubic meters of water.

This article about a dam or floodgate in Kantō region of Honshu, Japan is a stub.