Some of the important colonies that they had established in history are: Massalia, modern Marseille; Amisos in the Black Sea (now Samsun); Lampsakos in the Dardanelles (now Lapseki); Methymna (now Molyvos) on Lesbos; and Elea, now Velia (Italy); Alalia (Corsica).

Phocaea was taken over by the Genoese in 1275 as a fief from the Byzantine emperor, and was an active Port during the Middle Ages, principally due to the region's rich alum reserves.

The possessions of the Gattilusio family eventually grew to include, among others, the islands of Imbros, Samothrace, Lemnos and Thasos, and the city of Aenos (modern Enez in Turkey.

Many parts of the district are under strict environmental protection, due to the value of the flora and the fauna, and the beauty of the small bays and coves, especially between Foça and Yenifoça.

Because of the protective measures, new constructions are not permitted in many parts of the district and Foça is set to preserve its unique characteristic as composed principally of old houses.

The construction project for a 300-boat capacity marina in Foça is recently tendered and started, upon the completion of which the town is expected to open to more active international tourism.

Foça is the site of one of three marine protected areas established in Turkey for the preservation of the Mediterranean monk seal, a heavily endangered species of sea mammals.