Chalkidiki also spelled Halkidiki (/kælˈkɪdɪki/) or Chalcidice (/kælˈsɪdɪsi/) is named after the ancient Greek city-state of Chalcis in Euboea, which colonised the area in the 8th century BC.

The Cholomontas mountains lie in the north-central part of Chalkidiki, with the highest peak reaching 1,165 metres above sea level.

There are several summer resorts on the beaches of all three fingers where other minor towns and villages are located, such as at Yerakini (Gerakina Beach) and Psakoudia in central Chalkidiki, Kallithea, Chanioti and Pefkochori in the Kassandra peninsula, Nikiti and Neos Marmaras (Porto Carras) in the Sithonia peninsula, and Ouranoupolis at Mount Athos.

The climate of Chalkidiki is mainly Mediterranean (Koppen: Csa) with cool, wet winters and hot, relatively dry summers.

Later, the Greek colonies of the peninsula were conquered by Philip II of Macedon and Chalkidiki became part of Macedonia (ancient kingdom).

On a chrysobull of Emperor Basil I, dated 885, the Holy Mountain (Mount Athos) was proclaimed a place of monks, and no laymen or farmers or cattle-breeders were allowed to be settled there.

Today, over 2,000 monks from Greece and many other Orthodox Christian countries, such as Romania, Moldova, Georgia, Bulgaria, Serbia, and Russia, live an ascetic life in Athos, isolated from the rest of the world.

After a short period of domination by the Latin Kingdom of Thessalonica, the area became again Byzantine until its conquest by the Ottomans in 1430.

The survivors, among them Papas, were rescued by the Psarian fleet, which took them mainly to Skiathos, Skopelos and Skyros.

In June 2022, archaeologists announced the discovery of a poorly preserved single-edged sabre among the ruins of a monastery on the coast of Chalcidice.

Alongside the curved sword, excavators revealed evidence of a fire, a large cache of 14th-century glazed pottery vessels, as well as other weapons, including axes and arrowheads.

In September 2018 it was announced that Line 2 of the Thessaloniki Metro could be extended in the future in order to serve commuters to and from some areas of Chalkidiki.