Kosuge (小菅村, Kosuge-mura) is a village located in Yamanashi Prefecture, Japan.

The municipality consists of eight hamlets of Hashidate, Kawaike, Tadamoto, Nakagumi, Tobu, Shirasawa, Konagata, Nagasaku.

[1] Per Japanese census data,[2] the population of Kosuge has decreased over the past 60 years.

During the Edo period, all of Kai Province was tenryō territory under direct control of the Tokugawa shogunate.

During the cadastral reform of the early Meiji period on July 1, 1889, the village of Kosuge was created within Kitatsuru District, Yamanashi.