Kilkis (regional unit)

Kilkis Περιφερειακή ενότητα Κιλκίς
Regional unit
Municipalities of Kilkis
Kilkis within Greece
Coordinates: 41°0′N 22°50′E / 41.000°N 22.833°E / 41.000; 22.833Coordinates: 41°0′N 22°50′E / 41.000°N 22.833°E / 41.000; 22.833
Country	Greece
Region	Central Macedonia
Capital	Kilkis
Government
• Vice Governor	Christos Gountenoudis
Area
• Total	2,519 km2 (973 sq mi)
Population (2011)
• Total	80,419
• Density	32/km2 (83/sq mi)
Postal codes	61x xx
Area codes	234x0
ISO 3166 code	GR-57
Car plates	ΚΙ
Website	www.kilkis.gr

Kilkis (Greek: Περιφερειακή ενότητα Κιλκίς) is one of the regional units of Greece. 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 1,650 m or 5,413 ft). In the north, the Kerkini range straddles the border with the Republic of Macedonia. At 1,874 m or 6,148 ft 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 1,179 m or 3,868 ft). Lake Doirani is situated in the north, shared with the Republic of 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 Northern Macedonia (now the Rep. of Macedonia), especially from Gevgeli, Vogdantsa, Polyane and Stromnitsa.