| Kalu Ganga | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Sri Lanka |
| Length: | 1290NaN0 |
| Source1: | Sri Pada Peak Wilderness Sanctuary |
| Source1 Elevation: | 24000NaN0 |
| Mouth: | Indian Ocean |
| Mouth Location: | Kalutara |
| Mouth Elevation: | 1m |
| Basin Size: | 27660NaN0 |
| Tributaries Left: | Kukule River, wey River, Denawaka River, Hangamu River |
| Tributaries Right: | Kuru River, Induru River |
Kalu Ganga (Sinhala; Sinhalese: කළු ගඟ; literally: Black River) is a river in Sri Lanka. The river originates from Sri Pada Peak Wilderness Sanctuary, reaching the sea at Kalutara after a 1290NaN0 journey. The Black River flows through the Ratnapura and the Kalutara District and passes the city Ratnapura. The mountainous forests in the Central Province and the Sinharaja Forest Reserve are the main sources of water for the river.[1] The Edwardian manor, Richmond Castle is on the banks of the river near Kalutara.[2] [3] [4]