It travels northeast across the western side of Hokkaido to Asahikawa where it ends at an intersection with National Routes 39 and 40.

National Route 12 is a 135.7-kilometer-long (84.3 mi) highway in western Hokkaido that runs north from Sapporo to Asahikawa.

Its southern terminus lies at an intersection in Chūō-ku, Sapporo where it meets National Routes 36 and 230.

Ordered by Genrōin secretary Kaneko Kentarō, construction on the road began in April 1886.

The prison laborers were mainly political dissidents that Kaneko viewed as morally deficient.

[11] From its southern terminus with its parent route, it heads north and crosses over the Sorachi River.