So far, the blaze has consumed more than 10,800 acres in the Sheep Ridge Wilderness area of the forest. It was sending smoke as far away as the Triangle.
There were no reports of injuries or damage to property.
The Forest Service said it planned a prescribed burn Thursday through Saturday on about 2,000 acres along South Little Road near the center of the national forest, but it got out of control.
Pictures from Chopper 11 showed a towering column of smoke reaching hundreds of feet up into the atmosphere.
The state Division of Quality issued a Code Orange alert for residents of Carteret, Craven, Jones, Onslow and Pamlico counties, meaning the air could be unhealthy for sensitive groups. Air quality monitors as far west as Raleigh, about 125 miles away, have shown increased particle pollution due to smoke.