Kilkis prefecture is located in Central Macedonia (region of Hellas), between the prefectures of Pella, Thessaloniki and Serres. A large part of Kilkis lies in the verdant valley of Axios River, the ancient Amfaxitida. Its western and northern regions, include the sublime and forested mountains of Paiko and Belles, while Krousia(mountain range) on its northeast side and the Doirani Lake in the northwest, constitute a natural border as well as a splendid aquatic habitat with rare bird and plant species.
The region throughout appears to have been an area of human activity since the Copper and Iron Ages. Prehistoric settlements and interspersed tombs have provided significant findings dating back to the 2nd millennium BC.
On the west lies Peonia, a site Homer referred to by naming Axios, the earth's widest and most beautiful river.