The Narmada river largely forms the southern boundary of the Central Highlands, flowing mainly through a rift valley.

The river that largely forms the southern boundary of the Central Highlands is the Narmada River.
- **Location and Significance**:
The Narmada River is one of the major rivers in central India and flows mainly through the states of Madhya Pradesh and Gujarat. It is considered one of the holiest rivers in India and holds great religious significance.
- **Formation of the Southern Boundary**:
The Narmada River largely forms the southern boundary of the Central Highlands. The Central Highlands are a plateau region in central India, and the Narmada River flows along its southern edge, separating it from the Deccan Plateau to the south.
- **Physical Features**:
The Narmada River flows westward through a rift valley between the Vindhya and Satpura mountain ranges, which are part of the Central Highlands. The river has carved out a deep gorge in many places along its course, creating stunning landscapes.
- **Impact on the Region**:
The presence of the Narmada River has shaped the geography, ecology, and human settlements in the region. It has provided water for irrigation, supported diverse flora and fauna, and influenced the development of cities and towns along its banks.
- **Conclusion**:
In conclusion, the Narmada River plays a crucial role in defining the southern boundary of the Central Highlands. Its presence has not only influenced the physical features of the region but also its cultural and economic aspects.