Heidelberg is a town in Gauteng province, South Africa, located approximately 50 kilometres south-east of Johannesburg near the border with Mpumalanga. With a population of 35,500 inhabitants, it serves as a regional centre in the southeastern part of Gauteng. The town is positioned alongside the N3 highway, a major transport route connecting Johannesburg to Durban, making it a significant point along this corridor.
The town's notable geographic feature is its location at the eastern end of the Suikerbosrand Nature Reserve. This proximity to the reserve contributes to the area's natural environment and may offer recreational opportunities for residents and visitors. Heidelberg's strategic position—both as a town within Gauteng's network of settlements and as a gateway near the provincial border—has shaped its role within the broader Johannesburg metropolitan region.