The island of Poros is located at the South-West part of the Saronic Gulf, in a distance of 32 nautical miles from the port of Piraeus. It is divided from the coast of Troizinia with a narrow canal, the narrowest point of which has just 350-400 meters width. Kalavria along with Sfairia covers a surface of 31, 2 sq. km. and is alpine, like the whole Troizinia, but its crests have softer curves and, except of the few cultivated areas, it’s almost covered with pine trees. The shape of Kalavria is triangular and from the main body of the island, three peninsulas are standing out. To the north, there is the peninsula of Bisti, which ends up to the cape of “Achedo” (Bisti), to the south-east the peninsula of the Momnastery is extended, which ends up to the cape of “Kalavri” (Modi) and to the north-west the peninsula of Neorio is extended, which ends up to the cape of “Ntana” (Fanari), which is named like this because on its end, a lighthouse is built, which shows to the ships the entrance of the Gulf of Poros.

The island of Poros consists essentially of two islands that are united with a small isthmus of 150 m. width, Kalavria, which is all over green, full of pine forests, olive trees and lemon trees, and Sfairia, which is rocky, arid, but very beautiful and picturesque. There, the city of Poros is built in an amphitheatrically way, while the District, Askeli, Neorio, Fousa are found in Kalavria and Aluki, Artemis in Troizina. In antiquity, Kalavria and Sfairia were parted with a part of sea, which was pretty deep, and they comprised two separate islands. For this reason, Sfairia didn’t belong to the Kalavrian people, but to the Troizinians because it was closer to them. Pausanias, who visited the area on the 2nd century AC, reports that there was sea between the islands.

But the torrent that descends from the small vessel and the mountain of the Prophet Helias, transferring rubbles, soil, loose stones and sand, filled the sea that was between the two islands, united the two islands and transformed the channel that divided them into an isthmus that unites them. So, the place was created, where the district “Sunoikismos” is built nowadays.

This can be found out by the fact that the soil of “Suloikismos” is consisting of dirt and loose stones, which is of the same synthesis with these of Kalavria”s and are totally different from the bedrocks of Sfairia. The bedrocks of Sfairia are of trachyte, while the Kalavria’s are of limestone.

In 1877, A small channel was opened in the isthmus, a small canal, of 125 meters length, 4,80 m. width and 1-2 m. depth. From this canal, the boats can pass from the cove of the Progymnastirio, which is towards Askeli to the port of Poros or Neorio.

For the communication of the two parts of the island, a small bridge has been constructed, which has width as the existing road, the known bridge of the Progymnastirio.

Nowadays, the whole island, Kalauria and Sfairia, is called Poros. This name was taken by the narrow sea that is found between the city of Poros and the opposite coastal beach of Galatas, which is also the pass (poros) of the ships from the port of Poros to Hydra or the opposite. This narrow sea to the side of Peloponnese has very low depth and the pass of the ships is passed only in a curvy way towards the coast of Poros from the place “Kolona”, where the passengers’ ships come along side until the exit of the pass, at the place “Cross”.

The whole area of Troizinia belongs to the Nomarchy of Piraeus. The island of Poros (Sfairia – Kalavria) has a population of 3.929 inhabitants (census of 1981). Troizinia includes coastal sections of the south-east Argolida, the peninsula of Methana and the island of Poros. It covers a surface of 291 square kilometers and has a population of 11.809 inhabitants (census 1981). To the Municipality of Poros also beling the districts Aluki, Artemis, Lemon tree forest, Monastery of the Life Source, Blue Coast and Saint Nektarios (Fousa).

In the centre of the island of Kalavria, two mountains prevail, which are overgrown with pine trees. On the east part, there is “Vigla” with 378 m. height and in the middle of the island, the”Prophet Helias” with 314 m. height that on its peak, the homonym chapel of Saint Helias is built. The two mountains are uniting wit a neck of 1600 m. length, which is expanded at its beginning to the side of the Prophet Helias and a small plateau of 50.000 sq. m. is formed. It is “Polychron”. To the side of Vigla, this neck ends up to two small hillocks. On the hillock that is to the south, a small settlement is built, with approximately fifteen houses, and is named “Samuel”. In an approximately 600 m. distance from “Samuel” and 1000 m. from “Prophet Helias”, on the brow of the neck, the place “Palaces” is found, where there exists today everything has been left from the once upon a time bright temple of the God of the Sea , Poseidon. This place and everything standing in a ray of 500 meters around the sanctum of the temple have been abalienated and now belong to the Greek State.

The two mountains, “Vigla” and “Prophet Helias” are divided by a deep flume, “Tsoumpa”, which beginning from “Samuel”, reaches to “Askeli” and ends up to the place “Panagitsa”. In some points of the flume of “Tsoumpa” waters gush that flow and got lost in the flume, even during the summer. In winter, when it rains, this dry river carries much water and is transformed into a torrent, which ends up to “Askeli”.

The mountain “Vigla” on the north, descending to the sea, is divided into two hills. The west one is planted with pines and is smoother and reaches to the cove of Vayiona. On the north side of the hill, there are farms with olive trees and lemon trees. A bit down from the Temple of Poseidon and in a distance of 700 meters, the chapel of Saint Paraskeui is built.

The east hill is rocky, with bushy vegetation, ends up to the steep coasts of “Skarpeza” (Long channel). On the south-east of “Vigla”, three pine-planted hills are formed. They are “Staurorachi”, “Kokoreli” and “Tsoutsoura”, the plains of which end up steeply to the cave of “Modi”.

On the south of “Vigla”, two calm hills are formed, which also are full of pine trees. They are “Kiafa” and “Kontita”. On the plain of these hills, the great Monastery of the Source of Life is built, to which the biggest part of the around area also belongs.

The mountain of “Prophet Helias”, which is found in the centre of the island, has on its north-west part, slightly smooth plains, also full of punes, there are also though many fields cultivated with olive trees that reach to the field of “Fousa”. This field covers a surface of 300.000 sq. m., the biggest part of which is covered with vineyards that produce the great fousaetan wine. On the north-west point of Fousa, the chapel of Saint Antony is built and some cottages are found around it.

On the east point of Fousa, the chapel of Saint John is built, while a bit further on the plain, the chapel of Saint Nektarios is built. From that place the calm hills start, full of olive trees and lemon trees that reach to the cove of “Vayiona”. This is the place of “Kantali”. At this area, many natural springs with flowing water exist.

The climate of Poros has a cool summer followed by a mild winder and there's constant breeze blowing from the North which ensures a clear horizon.