Oligyrtos is a mountain located at the junction of Arcadia, Corinthia and Argolis in the northeastern Peloponnese in Greece. The mountain diagonally stretches from southwest to northeast, with about 35 km length and 15 to 20 km breadth. Its highest point is the peak Skipiza, at 1,935 m elevation. Other peaks are Gkrimini (1,831 m), Parnias (1,800 m), Skiathis (1,777 m) and Mavrovouni (1,695 m).
Neighbouring mountain ranges are Kyllini (Ziria) to the north, Mainalo to the southwest, Mount Trachi to the south and Chelmos (Aroania) to the northwest. Local flora consists mostly of grasslands and bushes. Pine trees and barren lands are found in higher areas. It is drained towards the Lake Stymphalia (which is located nearby Lake Doxa) to the north, and towards the plain of Kandila to the south.