The Neosho-class monitors were a pair of ironclad river monitors laid down in the summer of 1862. After completion in mid-1863, both ships spent time patrolling the Mississippi River against Confederate raids and ambushes as part of Rear Admiral David Porter's Mississippi Squadron. Both ships participated in the Red River Campaign in March–May 1864, although Osage supported the capture of Fort DeRussy in March and participated in the Battle of Blair's Landing in April. Osage was grounded on a sandbar for six months after the end of the campaign while Neosho resumed her patrols on the Mississippi. The latter ship supported the Union Army's operations on the Cumberland River and provided fire support during the Battle of Nashville in December.