| Beaver Mills | |
| Industry | Lumber |
| Founded | 1895 |
| Founder | Unknown |
| Defunct | October 7, 1910 |
| Successor | Rat Portage Lumber Company |
| Headquarters | Rainy River Rail links: Ontario and Rainy River Railway, Canadian Northern Railway |
| Services | Shipping company |
The Beaver Mills Lumber Company was a sawmill established in 1895 on the Rainy River in Northwestern Ontario, near the international border with Baudette, Minnesota. In 1910, as the Rat Portage Lumber Company, it was destroyed in the Baudette Fire.
