Mount Athos is a mountain on the eponymous peninsula in Macedonia, Greece. The peninsula is called the "Holy Mountain". In Classical times, the peninsula was called Akte. Its political status in Greece is known as the Autonomous Monastic State of the Holy Mountain. This World Heritage Site is home to 20 Eastern Orthodox monasteries and forms a self-governed monastic state within the sovereignty of the Hellenic Republic. Spiritually, Mount Athos comes under the direct jurisdiction of the Ecumenical Patriarchate of Constantinople.

The peninsula, the easternmost "leg" of the larger Halkidiki peninsula. The actual Mount Athos has steep, densely forested slopes reaching up to 6,670 ft. The surrounding seas, especially at the end of the peninsula, can be dangerous. In ancient Greek history two fleet disasters in the area are recorded: In 492 BC Darius, the king of Persia, lost 300 ships under general Mardonius. In 411 BC the Spartans lost a fleet of 50 ships under admiral Epicleas.

Though land-linked, Mount Athos is accessible only by boat. The daily number of visitors entering Mount Athos is restricted and all are required to obtain a special entrance permit valid for a limited period. Only males are allowed entrance into Mount Athos, which is called "Garden of the Virgin" by monks, and Orthodox Christians take precedence in the permit issuance procedure. Only males over the age of 18 who are members of the Eastern Orthodox Church are allowed to live on Athos, either as monks or as workers. There is a small number of unarmed religious guards, who are not monks, to keep order. Police and Coast Guard presence is very discreet. Residents not part of the religious communities are required to live in the peninsula's capital, Karyes.