Brnjavac is located in the municipality Gvozd, in Sisak-Moslavina County at an elevation of 188 meters above sea level and it covers the area of 5.99 km² (2.31 sq. miles). According to the 2011 census report, there were 95 inhabitants. It is predominantly populated by Serbs (91%), but also Croats (9%). Nearby places: Slavsko Polje, Crevarska Strana, Gvozd, Pješčanica, Podgorje, Gornji Sjeničak, Malešević Selo, Kozarac, Gornja Čemernica and Kirin.