The Abra River is the sixth largest river system in the Philippines in terms of watershed size. It has an estimated drainage area of 5,125 square kilometers and a length of 178 kilometers from its source in the vicinity of Mount Data in the Benguet province.
The Abra originates in the southern section of Mount Data. It descends westward to Cervantes, Ilocos Sur, and flows into Abra province. At a point near the municipality of Dolores, it is joined by the Tineg River, which originates in the uplands of Abra.