The Harts River (Afrikaans: Hartsrivier) is a northern tributary of the Vaal River, which in turn is the largest tributary of the Orange River (also known as the Gariep River, the largest river in South Africa). Its source is in the North West Province, but the greater part of its basin is located in the Northern Cape Province, which it enters a few kilometers downstream from the Taung Dam. The Harts forms a natural boundary for the , located between the Harts River and the .