The Rokkaku River originates up in the Jinroku Mountain in Yamauchi Town, Takeo City, which is located in western Saga. The Rokkaku River meets the Takeo River along the way, snakes through the Shiroishi Plain, and flows into the Ariake Sea. The impressive part around the mouth of the river is probably the well-built dikes on both sides of the sea. These were built because the area had often suffered from floods since early times.