The Lab originates from the Kopaonik mountain, between the Pilatovica and Bela Stena peaks, on the border of Kosovo and Serbia. The river flows southward, through the region of Upper Lab, by the villages of Marince, Bela Stena, Murgula, Brece and Metohija, receives several smaller streams from the Kopaonik and after it passes the village of Donja Pakaštica, the Lab enters the Malo Kosovo field.