Nagasaka (長坂町 Nagasaka-chō) was a town located in Kitakoma District, Yamanashi, Japan.
On November 1, 2004 Nagasaka was merged with the towns of Hakushū, Sutama and Takane, and the villages of Akeno, Mukawa and Ōizumi, all from Kitakoma District, to form the new city of Hokuto.
As of 2003, the town had an estimated population of 9,377 and a density of 229.49 persons per km². The total area was 40.86 km².