Kassandria is the only borough and at the same time the administrative and commercial centre of Halkidiki. It has about 2,500 inhabitants and it is built on the mainland of Kassanadra peninsula.

Its haven is Siviri with its excellent beach. Kassandria is a developing market town with considerable tourist infrastracture. The trip to the west passes through the mountainous Kassandria. To its north - west, there is a 19th century windmill that is worth visiting. At the coastline, there are the picturesque villages of Siviri, Skala Fourkas, Poseidi, Moles and Kalyves.