North of Pregrada, in the Kunagora region, is Kostelgrad, perched on a bend of the Kosteljina River. It is situated on top of a hill covered with deciduous forest at an elevation of 427 meters. The most prominent ruler of Kostelgrad was Petar Keglević.
The fortress is currently in a state of ruins, but there is an ongoing project to consolidate the walls, financed by the Ministry of Culture. Kostelgrad is a popular excursion spot that offers a beautiful view of the Sutinska Valley, a narrow passage along the Kosteljina River, which leads into the town of Pregrada from the north. Access to the fortress is easy and accessible from the north, near the settlement of Kostel.