Nishiyama (西山町; -machi) was a town located in Kariwa District, Niigata, Japan.
As of 2003, the town had an estimated population of 6,712 and a density of 118.52 persons per km². The total area was 56.63 km².
On May 1, 2005 Nishiyama, along with the town of Takayanagi, also from Kariwa District, was merged into the city of Kashiwazaki.