Hardap is one of the fourteen regions of Namibia, its capital is Mariental. Hardap contains the municipality of Mariental, the towns Rehoboth and Aranos, and the self-governed villages Gibeon, Gochas, Kalkrand, Stampriet and Maltahöhe. It is home to the Hardap Dam.

Mariental is a town of 10,000 inhabitants in south-central Namibia, lying on the B1 national road 232 kilometres (144 mi) north of Keetmanshoop and 274 kilometres (170 mi) southeast of Windhoek. It lies at an elevation of 1,090 metres (3,580 ft). Mariental is connected to the TransNamib railway line from Windhoek to Keetmanshoop. The town and the surrounding area are situated in a hot, arid region.