Trnova is located in the municipality Dubrovačko Primorje, in Dubrovnik-Neretva County at an elevation of 313 meters above sea level and it covers the area of 6.54 km² (2.53 sq. miles). According to the 2011 census report, there were 43 inhabitants. It is entirely populated by Croats. Nearby places: Mravnica, Banići, Kručica, Slano, Podgora, Podimoć, Čepikuće, Lisac and Doli.