Kur and Araz run through the Kur-Araz lowland. The rivers that directly flow into the Caspian Sea, originate mainly from the north-eastern slope of the Major Caucasus and Talysh mountains and run along the Samur-Devechi and Lenkeran lowlands.

Azerbaijan river systems are changing and evolving under the influence of various physiographic factors: climate, landscape, geological structure, soil and vegetation. The density of the river network increases, then gradually decreases later with higher altitudes. Except for the Talysh region (1.6-2.2 km/sq.km), the river system density is the highest (1-2km/sq. km) at 1,000-2,500 kilometers, while in the area of the Talysh mountains it peaks at 1.6-2.2 km/sq.km at 500-1,000 km. The average density of the river system of Azerbaijan is 0.39 km/sq.km. The density is even lower than 0.05 km/sq.km in the plains.

The Kur River basin area (86,000 sq. km) up to the junction with the Araz River is smaller than the Araz water basin (101,937 sq.km). The river is still called Kur on the junction because the water level of the Kur is twice as high as that of the Araz River.