Mravnica is located in the municipality Dubrovačko Primorje, in Dubrovnik-Neretva County at an elevation of 151 meters above sea level and it covers the area of 8.40 km² (3.24 sq. miles). According to the 2011 census report, there were 37 inhabitants. It is predominantly populated by Croats (97%), but also. Nearby places: Trnova, Banići, Podgora, Podimoć, Kručica, Čepikuće, Slano, Lisac and Doli.