The area of the modern town of Yosano was within ancient
Tango Province, and the place name of "Yosa" dates from records of the early 8th century. In the
Edo Period, it was part of the area was controlled by
Miyazu Domain. The town of
Kaya and villages of Yosano and
Iwataki were established within
Yosa District with the creation of the modern municipalities system on April 1, 1889. On April 1, 1921, Iwataki was raised to town status. On December 1, 1954, Yosano merged with Kaya. On March 1, 1955, five villages merged to form the town of
Nodagawa. Kaya, Iwataki and Nodagawa merged to form the town of Yosano on March 1, 2006. ==Government==