Donje Gnojnice is located in the municipality Cetingrad, in Karlovac County at an elevation of 210 meters above sea level and it covers the area of 0.49 km² (0.19 sq. miles). According to the 2011 census report, there were 20 inhabitants. It is entirely populated by Croats. Nearby places: Gnojnice, Gornje Gnojnice, Tatar Varoš, Dubrave, Kapljuv, Bilo, Lađevačko Selište, Miljevac, Arapovac and Salopek Luke.