The Ralja ( Serbian Cyrillic: Раља) is a river in Šumadija region of Serbia, a 51 km long left tributary to the Jezava, the left arm of the Great Morava river. It also gives its name to the surrounding Šumadija's subregion of Ralja.
The Ralja originates from the northern part of the Kosmaj mountain, north of the village of Velika Ivanča, in the Sopot municipality of the City of Belgrade. Almost from the source, the river valley is a route for the Belgrade- Niš railway. At the villages of Popović and Mali Požarevac, the Ralja turns straight to the east for the rest of its flow and also from this point, the Belgrade-Niš highway joins the railroad.
As it flows next to the Belgrade suburbs of Dražanj, Umčari and Živkovac, the Ralja divides Podunavlje region from the Ralja region of the low Šumadija, and leaves the City of Belgrade area at the village of Malo Orašje. After the villages of Binovac, Kolari, Vrbovac and Ralja, the river separates from the highway turning north at the village of Vranovo and empties into the one of several arms of Jezava at the Smederevo's suburb of Radinac.
The Ralja drains an area of 310 km², belongs to the Black Sea drainage basin and it is not navigable.
Ralja is a village in the municipality of Smederevo, Serbia. According to the 2002 census, the village has a population of 1537 people.
Ralja is a village in the municipality of Sopot, Serbia. According to the 2002 census, the village has a population of 2858 people.
Ralja can refer to several locations in Serbia:
- Ralja (river)
- Ralja (Smederevo), village near Smederevo
- Ralja (Sopot), village near Sopot