Çiğli (Silleon in Greek) is a metropolitan district of İzmir in western Turkey. It covers the northern end of İzmir Metropolitan Municipality around the mouth of the River Gediz, across the Gulf of İzmir from the main city. The Gediz delta is an Important Bird Area but is under threat from urbanization. IAOIZ, the Izmir Atatürk Organized Industrial Zone, is a significant economic hub and there is a major air force base.