Agios Athanasios (Άγιος Αθανάσιος) is a municipality in the Thessaloniki Prefecture, Greece. Thessaloniki (Θεσσαλονίκη is a Nomos ( Prefecture) in Greece, containing Thessaloniki, Lagana and the northern portion Greece (Ελλάδα transliterated: Elláda, historically, Ellás,) officially the Hellenic Republic (Ελληνική Δημοκρατία Population 14,387 (2001).