Afrikaans name: Wilgerivier
The source of the Wilge River is near the border between Free State and KwaZulu-Natal near Swinburne. The Wilge River ends when it flows into the Vaal Dam.
Sterkfontein Dam is on the Wilge River. Water in the dam is predominantly pumped from KwaZulu-Natal to help supplement the water supply in Gauteng.
Along its course the Wilge River is joined by the Meul River, Cornelis River and Liebenbergsvlei.