Local compartment of Smynos Municipality. On the road Aigies-Arna, we first come across Petrina. This is the biggest local compartment of the Municipality with 450 inhabitants (census 2001). Of course, in summertime, they are more than 1000. The population has had many fluctuations till now. In 1940, it was 942 inhabitants, in 1951, 908, in 1971, 448, in 1981, 444 and in 1991, 309. Petrina belongs to the lowland of the Municipality and covers an area of 29.400.000m2. The 7.000.000m2 are cultivated area, the 15.000.000m2 are forested area and the rest is pastoral land.

As in the rest of Mani, Petrina went through the immigration flow to USA and Canada. As a result, people coming from Petrina, created centres over there and never forgot the place where they come from. They often visit Petrina and even contribute financially to the development of their village.

The history of the village is very old. Firstly, in 1304, Petrina is mentioned along with the hagiographer Theodoros Petriniotis in written sources. In Byzantine times, Petrina, along with Geraki and Mystras is also mentioned. In the National Struggle, in 1821, the inhabitants of Petrina took part in the liberation struggle and prove to be noteworthy heroic personalities and national benefactors, such as the first mayor of Krokees, who had his headquarters in Petrina, Panagiotis Anagnostakis, who offered a significant amount of money to the struggle. Indisputable proof about the participation of the inhabitants of Petrina to the struggles of the nation is the old canon in Rahidi from 1821, as well as plenty of photographic material about their participation to the Macedonian Struggle in 1st and 2nd World War.

In recent times, the Agricultural Cooperation of Petrina, founded in 1915, acquired the “Protected Designation of Origin” for the olive oil they produce.

The Union of Attorneys (before 1907) and later the Welfare Institution of Petrina, is active offering services to the society. In the area, there is, since 1915, the aqueduct and the abattoir. Additionally, in Petrina there is the KEΠ of the Municipality.

In Petrina, one can try his shooting abilities at the shooting centre near the road Gythion-Sparta. It should be noted that the natural and animal richness of the area has led to the creation of a refuge for partridges, hares and pheasants.

In Petrina, there are many churches; some are built in the beginning of the 19th century with important frescos and icons. Prophet Eias, Ai Jiorgis, Ai Thanasis, Ai Dimitrios, are all Byzantine churches of the 13th century. Panagitsa at Hiotika, constructed in 1800, has important frescos and icons, too. There are also Agios Panteleimon built in 1900, Sotiros church in 1900 and Agii Apostoloi Petros and Pavlos, which is the parish church at the central square of the village with important frescos.

In Petrina, one can visit the springs Housou Platani, which are traditional springs, where a statue of the ancient Greek times was found; this is kept at the archaeological museum in Sparta. The big poet and academic Nikiforos Vrettakos comes from Petrina and his name is listed in the files of the community.

In the village, there is an atmosphere of creation. In this effort, the collective activity of the inhabitants plays an important role. This is expressed through the Welfare Institution and the Agricultural Cooperation. Innovative institutions that were formed decades ago are still active in everyday life and ameliorate the living conditions of the area.