The Borovitsa (Bulgarian: Боровица) is a 42 km long river in southern Bulgaria, a left tributary of the Arda of the Maritsa drainage.

[1] Along its low course and its tributary the Ayladere passes the boundary between the western and the eastern Rhodope Mountains.

The river takes its source under the name Hambardere at an altitude of 1,622 m on the northern foothills of the summit of Elvarnika (1,715 m) in the Pereliksko–Prespanski Ridge of the western Rhodope Mountains.

It initially flows in northeastern direction, gradually turning to the southeast and forming a large arc bulging to the north.

[1] Near its confluence with the Arda at the modern Kardzhali Reservoir are located the ruins of the medieval Patmos Fortress.