In 1757, during the Turkish occupation, and after the castle of Kalloni was abolished, the castle of Sigri was built on the foundations of the earlier, much smaller fortification erected by the Venetian Gatelouzos. According to historical sources, the first inhabitants of the castle were Turks formerly imprisoned in the fortress, who after their release chose to return there with their families. Gradually populations that had first occupied the mainland, such as Muslim janissaries (Turkish elite troops) settled in the area. Subjugation, oppression and taxation of the local Greek people acted as a deterrent to the settlement of Christian populations. In 1885 it was reported that there were 60 houses, and 200 in 1908, with an entirely Muslim population.
At least until the end of the 19th century the fortress was the center around which the settlement developed. Throughout the 19th century and until 1912 it maintained a military presence. According to the testimonies of the deputy consuls of France (1858) and Russia (1895) the castle was well maintained and equipped to prevent any local unrest but could not have withstood a coordinated attack from the sea.
In the early years of the 20th century the first Greek families from Andissa and Eresos came to live in Sigri and in 1923, due to the exchange of populations imposed by the Treaty of Lausanne, the Turks left Sigri, and refugees arrived from Tenedos, from the area of Propontis (mainly from Houchlia, but also from Constantinople, Phocaea, Moschonisia), from the area of Smyrna, and from other parts of Asia Minor.
At that time, Sigri had a small merchant fleet. Most, however, were sunk during the German occupation during WWII and very little remainedof the fleet.
Sigri like most of Greece was also hit by post war migration. Many people left for other parts of the world: Australia, USA, Canada and Germany, or for Athens, Thessaloniki and elsewhere in Greece. At the official census of 2011, Sigri had 333 inhabitants.