Korinthia has a few uninhabited islets, called the Alkyonides (Prasonisi, Glaronisi Zodohos Pigi and Daskalio) in addition to others, which could be interesting to visit. It is a mountainous prefecture with the mountains on the western side being the highest. These include Ziria or Kyllini, Saita and Oligyrtos).
There are very green regions in the Gerania mountains and in Onia. Sitting under the cherry trees in Evrostina is an experience in itself. The dried up lake of Stymphalia (see below) on the Peloponnese side and salty lake of Vouliagmeni near Loutraki on the mainland side offer great escapes. The latter was actually an underground cave once upon a time which collapsed to yield a lake.
Photo: Nojos88