| Conflict: | Rainbow Bluff Expedition |
| Partof: | the American Civil War |
| Date: | December 9, 1864 |
| Place: | Roanoke, North Carolina |
| Result: | Confederate victory |
| Combatant1: | United States (Union) |
| Combatant2: | CSA (Confederacy) |
| Commander1: | David Porter Innis N. Palmer |
| Commander2: | |
| Strength1: | 2 Gunboats |
| Strength2: | Several Water mines |
| Casualties1: | Otsego and Basely sunk |
| Casualties2: | none |
The Rainbow Bluff Expedition took place on December 9, 1864 during the American Civil War. The Confederate water mines caused the Union naval force to cancel the expedition.
On 9 December, an expedition, which included the gunboat USS Wyalusing, moved farther up the Roanoke to capture Rainbow Bluff and a Confederate ram, rumored to be under construction at Halifax, North Carolina. While anchoring near Jamesville, North Carolina, Otsego, another gunboat, struck two torpedoes (mines) and sank up to her gun deck. Bazely, a tug, moved alongside Otsego to offer assistance, but she, too, struck a torpedo and sank immediately. Wyalusing and the remainder of the expedition left the two partially sunken ships under the protection of their own unsubmerged guns and headed upriver, cautiously dragging for torpedoes as they went. By the time they had reached the point of attack, the Confederate positions at Rainbow Bluff had been so well reinforced and the approaches so heavily strewn with torpedoes that the Union ships had to abandon the enterprise. Wyalusing and her consorts returned to Plymouth on 28 December 1864 and resumed blockade and amphibious support duties.