was a town located in Santà  District, Niigata Prefecture, Japan.
As of 2003, the town has an estimated population of 7,535 and a density of . The total area is .
On April 1, 2005, Mishima, along with the town of Oguni (from Kariwa District), the village of Yamakoshi (from Koshi District), the town of Nakanoshima (from Minamikanbara District), and the town of Koshiji (also from Santà  District), was merged into the expanded city of Nagaoka.
had been operated in the town until 1975.