Sastavak is located in the City of Slunj, in Karlovac County at an elevation of 440 meters above sea level and it covers the area of 2.67 km² (1.03 sq. miles). According to the 2011 census report, there were only 14 inhabitants. It is largely populated by Croats (88%), but also Serbs (13%). Nearby places: Kosa, Donji Furjan, Gornji Furjan, Zapoljak, Trnovi, Brezovac, Polje, Mašvina, Bogovolja and Koranski Lug.