| Calder | |
| Name Etymology: | River Calder in England |
| Map Size: | 250 |
| Pushpin Map: | Australia Victoria |
| Pushpin Map Size: | 250 |
| Pushpin Map Caption: | Location of the Calder River mouth in Victoria |
| Subdivision Type1: | Country |
| Subdivision Name1: | Australia |
| Subdivision Type2: | State |
| Subdivision Name2: | Victoria |
| Subdivision Type3: | Region |
| Subdivision Name3: | South East Coastal Plain (IBRA), The Otways |
| Subdivision Type5: | Local government area |
| Subdivision Name5: | Colac Otway Shire |
| Length: | 14km (09miles) |
| Source1: | Otway Ranges |
| Source1 Location: | near Bateman Ridge |
| Source1 Coordinates: | -38.7081°N 143.5711°W |
| Source1 Elevation: | 393m (1,289feet) |
| Mouth: | confluence with the Aire River |
| Mouth Location: | south of Lake Craven |
| Mouth Coordinates: | -38.7978°N 143.4786°W |
| Mouth Elevation: | 0m (00feet) |
| River System: | Corangamite catchment |
| Custom Label: | National park |
| Custom Data: | Port Campbell National Park |
| Extra: | [1] [2] |
The Calder River is a perennial river of the Corangamite catchment, located in the Otways region of the Australian state of Victoria.
The Calder River rises in the Otway Ranges in southwest Victoria, near Bateman Ridge and flows generally south by west through the Port Campbell National Park towards the settlement of Horden Vale where the river enters Lake Costin and then Lake Craven, before reaching its confluence with the Aire River shortly before the Aire enters Bass Strait, northwest of Cape Otway. From its highest point, the Calder River descends over its 14km (09miles) course.[2]
The river was named by surveyor George Smythe after the River Calder in Yorkshire, England, similarly a tributary of the River Aire.[3]