Sannosawa No.1 Dam (Japanese: 三の沢第一ダム) is an earthfill dam located in Hokkaido Prefecture in Japan. The dam is used for irrigation. The catchment area of the dam is 1.6 km2. The dam impounds about 11 ha of land when full and can store 710 thousand cubic meters of water. The construction of the dam was completed in 1924.