Kilkis (regional unit)

Kilkis (Περιφερειακή ενότητα Κιλκίς) is one of the regional units of Greece, in the geographic region of Macedonia. It is part of the region of Central Macedonia. Its capital is the city of Kilkis. The geography of the regional unit of Kilkis is characterized by the wide and flat Axios river valley in the westcentral part, and mountain ranges on its western and northeastern edges. The mountain range in the west, on the border with Pella regional unit, is Mount Paiko (highest peak ). In the north, the Kerkini range straddles the border with North Macedonia. At the highest peak in Kilkis regional unit is located here. The border with Serres regional unit to the northeast is formed by the lower Kroussia range (highest peak ). Lake Doirani is situated in the north, shared with North Macedonia. Kilkis borders the Thessaloniki regional unit to the south. The climate of the Kilkis regional unit is humid continental in the north, and humid subtropical in the lower regions. The area of the modern regional unit was part of the Kingdom of Macedonia from the 8th century BC until the Third Macedonian War (171 BC - 168 BC), when it became a part of the Roman Empire. At the division of the Roman Empire in 395 AD, the area joined the eastern part, later known as the Byzantine Empire. Between the 7th century and the 11th century, it changed hands between the Byzantine Empire and the Bulgarian Empire repeatedly. In the 13th and 14th century Western Europeans and Serbs briefly ruled the area. The Ottoman Empire conquered the area in 1371, and ruled it until the First Balkan War of 1912. In the Second Balkan War of 1913, the Greek army captured the area, which became part of Greece. It absorbed many of the Greeks from what is now the Republic of North Macedonia, especially from Gevgeli, Vogdantsa, Polyane and Stromnitsa. In the aftermath of the Balkan Wars, World War I and the Greco-Turkish War (1919-1922) most of the Turkish and Bulgarian population of Kilkis emigrated, and many Greeks from Bulgaria, North Macedonia and Turkey settled in the area, as prescribed by the Treaty of Lausanne (1923).