Gornje Postinje is located in the municipality Muć, in Split-Dalmatia County at an elevation of 446 meters above sea level and it covers the area of 6.24 km² (2.41 sq. miles). According to the 2011 census report, there were 134 inhabitants. It is entirely populated by Croats. Nearby places: Donje Postinje, Donji Muć, Radunić, Gornje Ogorje, Bračević, Brštanovo, Donje Ogorje, Gornji Muć, Ramljane and Mala Milešina.