Kastanas (Greek: Καστανάς, [kasta'nas]) is a village of the Chalkidona municipality.

Before the 2011 local government reform it was part of the municipality of Koufalia.

[2] The 2021 census recorded 483 inhabitants in the village.

[1] The population of Kastanas consists mainly of Greek refugees from İzmit, but there are also smaller numbers of Sarakatsani and Greek refugees from Bulgaria.

[3] The village was formerly known as Kara Oglu (Greek: Καρά Ογλού, [ka'ɾa o'ɣlu], from Turkish: Kara Oğlu).