The regional unit stretches from the Thermaic Gulf in the southwest to the Strymonic Gulf in the east.
Two bodies of water are located in the north, Lake Koroneia in the heart of the regional unit and Lake Volvi in the east.
There are farmlands throughout the west and southwest, with fewer in the northeast, north and along the Axios River valley.
Mountainous areas include the Chortiatis in the west-central part, the Vertiskos in the north and parts of the Kerdylio mountains in the northeast.
The regional unit borders on the Imathia regional unit to the southwest, Pella to the west, Kilkis to the north, Serres to the east and Chalkidiki to the south.

Its climate includes hot Mediterranean summers and cool to mild winters in low-lying areas and plains.
Winter weather is very common in areas 500m above sea level and into the mountains.
The regional unit stretches from the Thermaic Gulf in the southwest to the Strymonic Gulf in the east. Two bodies of water are located in the north, Lake Koroneia in the heart of the regional unit and Lake Volvi in the east. There are farmlands throughout the west and southwest, with fewer in the northeast, north and along the Axios River valley. Mountainous areas include the Chortiatis in the west-central part, the Vertiskos in the north and parts of the Kerdylio mountains in the northeast. The regional unit borders on the Imathia regional unit to the southwest, Pella to the west, Kilkis to the north, Serres to the east and Chalkidiki to the south.
Its climate includes hot Mediterranean summers and cool to mild winters in low-lying areas and plains. Winter weather is very common in areas 500m above sea level and into the mountains.
Thessaloniki (regional unit)