Kobiljača is located in the municipality Pojezerje, in Dubrovnik-Neretva County at an elevation of 25 meters above sea level and it covers the area of 5.24 km² (2.02 sq. miles). According to the 2011 census report, there were 246 inhabitants. It is entirely populated by Croats. Nearby places: Brečići, Mali Prolog, Dubrave, Pozla Gora, Plina Jezero, Otrić-Seoci, Staševica, Borovci, Veliki Prolog and Peračko Blato.