They are situated between the towns of Trenčín, Považská Bystrica, Rajec, Prievidza and Bánovce nad Bebravou, bordering White Carpathians and the Váh river in the northwest and west, Javorníky in the north, Malá Fatra in the east, Vtáčnik and Nitra river in the south and Považský Inovec in the southwest.

Whole mountain range is a Miocene horst that modifies older Mesozoic nappe structure.

The lower Fatric Unit composed of Lower Triassic to Cenomanian sediments of two types, the Zliechov succession, distinguished by deep marine Jurassic facies and the Belá succession with the shallow marine facies deposited in the same time.

Uppermost nappe unit of the nappe structure is called the Hronic unit, with the Carboniferous-Permian extensive volcanosedimentary succession (Ipoltica Group) and Triassic, less often Jurassic-Lower Cretaceous limestones and dolomites (the Čierny Váh, Biely Váh and Bebrava successions).

[3] In the NW portion of the mountain range the boundary with the Pieniny Klippen Belt consists of the Manin unit that is probably a frontal element of Fatric unit incorporated into Klippen Belt strike-slip zone.