[6] Immediately to the south of the castle lies Korissia Lake which is separated from the sea by a narrow strip of land.

[7][8] Remains from the upper Paleolithic era, dating from 20,000 B.C., when Corfu was still united to the mainland region of Epirus, were found on the site of the castle at the rock shelter of Grava Gardikiou, including hunter-gatherer stone tools and animal bones,[9] which have since been removed and are exhibited at the Archaeological Museum of Corfu.

[3][4][11] The walls of Gardiki Castle form an octagon and the structure features eight strong towers decorated by rows of tiles.

At the top of the southern tower there are traces of a chapel with remnants of religious frescoes of portraits of saints.

[12] Corfiote noble Andrea Marmora,[13] the earliest historian of Corfu in medieval times, in his 1672 book Della Historia di Corfù mentions that the despots of Epirus adorned the city of Corfu with "most noble buildings" and built defences in other places on the island, including the fortresses of Gardiki and Angelokastro amongst other important sites.