Donje Planjane is located in the municipality Unešić, in Šibenik-Knin County at an elevation of 300 meters above sea level and it covers the area of 9.48 km² (3.66 sq. miles). According to the 2011 census report, there were 37 inhabitants. It is entirely populated by Croats. Nearby places: Ostrogašica, Sedramić, Gornje Planjane, Podumci, Mirlović Zagora, Žitnić, Pakovo Selo, Unešić, Moseć and Pokrovnik.