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 51.9 kilometers (32.2 mi) on land, but a total length of 163.2 kilometers (101.4 mi) with the distance traveled by the Sado Steam Ship across the Sea of Japan factored in.

[2] It has a total length of 51.9 kilometers (32.2 mi) on land, but a total length of 163.2 kilometers (101.4 mi) with the distance traveled by the Sado Steam Ship across the Sea of Japan factored in.

In response, officials on Sado Island sought assistance from the national government to improve the roads of the island; however, the law governing Japan's national highways only allowed for highways that were connected to core cities, special cities, and prefectural capitals to be designated as national highways.

These officials petitioned the then-Secretary-General of the Liberal Democratic Party, Kakuei Tanaka, to give the island a national highway by finding a loophole in the law.