Mainalo mountain is in Tripoli municipality, in Arcadia region. Its tallest peak is Ostrakina (Of Shells, in Greek), with a total height of 1,981 metres. It takes up the largest part of north Arcadia, though the mountain takes up about 175,000 acres, while overall taking up more than twice the area.
The name Mainalo meant, in ancient Greek, the "sacred rage of wild nature". It is a mountain of long history, since the ancient Arcadians built important cities there, like Orchomenos, Mantineia, Ypsous and Tegea. The worship of god Pan was widespread in the area. During the Middle Ages, the area saw many Slavic migrants, as can be seen in the place names to this day. During the Greek Revolution against the Turkish rule in 1821, because of how hard to reach were most places of the wild landscape, the area had an important role. It provided the fighters with important resources, such as the gunpowder mills of Dimitsana and, of course, safe shelter against the enemy.
The area's flora is rich, though fires destroyed much in 2011, such as the fir forest of the mountain's northwest side. Other species of trees that grown on the mountain are the cypress, the oak, the pine tree, many types of herbs and low shrubs, and it is known that the mountain is incredibly rich in fungi, that is, mushrooms. The ecosystem of Mainalo has been registered under the Natura 2000 protection treaty.
Lousios river has its spring on Mainalo mountain, and in its canyon were built interesting monasteries during the medieval times, that still attract visitors.
In recent years, with the cooperation of the residents of the surrounding settlements, the mountain has been developed touristically. The visitor can now enjoy the mountain all year long, thanks to the Ski Resort and the Retreat in Ostrakina; hiking during the summer and winter sports during the colder seasons.