Thessaloniki is one of the regional units of Greece. It is part of the Region of Central Macedonia and its capital is the city of Thessaloniki. The r…Thessaloniki is one of the regional units of Greece. It is part of the Region of Central Macedonia and its capital is the city of Thessaloniki. 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.