Macedonia is a geographic and former administrative region of Greece, in the southern Balkans. Macedonia is the largest and second-most-populous geographic region in Greece, with a population of 2.36 million. It is highly mountainous, with major urban centres such as Thessaloniki and Kavala being concentrated on its southern coastline. Together with Thrace, along with Thessaly and Epirus occasionally, it is part of Northern Greece. Greek Macedonia encompasses entirely the southern part of the wider region of Macedonia, making up 51% of the total area of that region. Additionally, it widely constitutes Greece's borders with three countries: Albania to the northwest, North Macedonia to the north, and Bulgaria to the northeast.

Thessaloniki, also known as Thessalonica, Saloniki, Salonika, or Salonica, is the second-largest city in Greece, with slightly over one million inhabitants in its metropolitan area, and the capital of the geographic region of Macedonia, the administrative region of Central Macedonia and the Decentralized Administration of Macedonia and Thrace. It is also known in Greek as "η Συμπρωτεύουσα", literally "the co-capital", a reference to its historical status as the Συμβασιλεύουσα or "co-reigning" city of the Byzantine Empire alongside Constantinople.