Belaj is located in the municipality Cerovlje, in Istra County at an elevation of 125 meters above sea level and it covers the area of 5.31 km² (2.05 sq. miles). According to the 2011 census report, there were 16 inhabitants. It is entirely populated by Croats. Nearby places: Letaj, Paz, Gradinje, Šušnjevica, Boljun, Boljunsko Polje, Grobnik, Zankovci, Kostrčani and Nova Vas.