Kastanoussa (Greek: Καστανούσσα), known before 1926 as Palmes (Greek: Πάλμες),[2] is a village and a community in Serres with a population of 635 inhabitants as recorded in the 2021 census.

The village is located in the southern foothills of Belasitsa, near the borders with North Macedonia and Bulgaria.

In 1891 Georgi Strezov wrote: Palmesh, several neighbourhoods on the west of Poroy [modern name of Ano Poroia], 6 hours drive at the foot of Belasitsa and Pear mountain.

They speak Bulgarian with a slight difference from Poroy; they dress in a special red garment-anther and poturi.

Ethnography and Statistics") by 1900 "Palmesh" ("Palmesha") is a Bulgarian Muslims' settlement .