mountain range in Western Cape province, South Africa, extending east-west for 150 mi (240 km) from near the town of Willowmore to the edge of the Witteberge, roughly parallel with the Indian Ocean coast. The Swartberg is the barrier dividing the semiarid Great Karoo (north) and Little Karoo (south) plateaus. Highest elevations range from between 5,500 and 7,500 ft (1,650 and 2,300 m). Small reservoirs amid the peaks supply water to adjacent lowland areas; and gorges, secluded valleys, sheer rock faces, and caves are popular with the adventuresome.