Ciomadul is formed by a complex of lava domes and other volcanic material that form a south-tilting ridge that rises above the high surrounding Lower Ciuk Basin. Individual lava domes form cone-shaped hills, which reach heights of and widths of . Individual domes include Haramul Ierbos (Fű-Haram in Hungarian), Haramul Mare (Nagy-Haram), Haramul Mic (Kis-Haram), Vf. Cetăţii (Vár-tető), Vf. Comloş (Komlós-tető), Vf. Surduc (Szurdok-tető) and Dealul Mare southeast from the main complex. The central cluster of domes is elliptical. The highest point of the complex is Ciomadul Mare (Nagy-Csomád) with an altitude of . Some domes were later affected by erosion, explosive activity or fumarolic alteration. The whole volcanic complex covers a surface area of , and is surrounded by a circular/semicircular plain made of volcanic debris.