The massif is formed by a crest of limestone summits aligned north-west to south-east all in a row at the south of the province of Gipuzkoa, namely Artzanburu, Andreaitz, Arbelaitz (1,513 m), Iraule (1,511 m), Aitxuri, Aketegi (1,549 m) and Aizkorri (1,528 m).

The major Madrid-Irun railway cuts its way through the northern steep slopes of the mountain range, with two train stops, i.e. Otzaurte and Zegama Apeadero hardly operating any longer.

The initial mud track going up west (PR-GI 70) peters out into a narrow trail at a major crossroads (col of Intzuzaeta) after taking a turn south-west.

Yet the main ascension route comes from the south-west, from the Sanctuary of Arantzazu (Oñati),[1] where a beaten trail goes up through a thick forest of beeches and ends at the Urbia meadows.

The Zegama-Aizkorri Marathon,[2] a popular cross-country endurance race, takes place in spring along a loop circuit around the Aizkorri massif (sometimes including Aratz).