is a national highway of Japan that traverses the prefecture of Niigata in a southwest–northeast routing. It connects the city of Jōetsu in southern Niigata Prefecture to the prefecture's capital city, Niigata, to the north along the Sea of Japan coastline; however the highway mainly functions as the main highway on Sado Island. It has a total length of on land, but a total length of with the distance traveled by the Sado Steam Ship across the Sea of Japan factored in.
