is a town located in Asa District, Yamaguchi Prefecture, Japan.
As of 2003, the town has an estimated population of 22,131 and a density of 246.42 persons per km2. The total area is 89.81 km2.
On March 22, 2005, San'yō, along with the city of Onoda, was merged to create the city of San'yō-Onoda.[1]