[1] The stream originates from two springs in the Marjayoun (Merj 'Ayun) valley in southern Lebanon,[5] runs southward for seven kilometers through various irrigation ditches, then flows into Israel near Metulla, where it continues through the Hula Valley in the Galilee Panhandle[6] until emptying in the Hasbani River just before it reaches the Jordan River.

In the watershed of Nahal Ayun, an average of about 900 millimeters of rain falls annually, causing significant variations in water flow between seasons.

Even in Israel, it primarily serves agricultural irrigation near Metula, resulting in minimal flow in its lower part during the summer.

To address this, the Israel Nature and Parks Authority has been artificially diverting water since 2009 from boreholes in the Dan River area during the summer months.

[5][7] However, the Survey map actually uses another name altogether for the upper course, Wadi el Kharrar,[8] "the valley of the murmuring water".