| Castor River | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | Ontario |
| Length: | 24km (15miles) |
The Castor River is a river in eastern Ontario, in Canada. It flows from Russell, Ontario[1] into the South Nation River near Casselman.[2] It has a number of branches, including the North, Middle, South and East Castor Rivers which join in Embrun. The river was named for the many beaver dams found in its watershed; "castor" means "beaver" in French.