Donji Brgat is located in the municipality Župa Dubrovačka, in Dubrovnik-Neretva County at an elevation of 257 meters above sea level and it covers the area of 3.78 km² (1.46 sq. miles). According to the 2011 census report, there were 152 inhabitants. It is predominantly populated by Croats (99%), but also. Nearby places: Gornji Brgat, Grbavac, Čelopeci, Martinovići, Šumet, Makoše, Mandaljena, Knežica, Čibača and Buići.