Alexander “Possum” Gillespie, 50, of Fayetteville, is a civilian employee at Fort Bragg.
He kayaking on the river Sunday with two other people, who made it safely to shore.
Fort Bragg Emergency Services personnel have coordinated a rescue effort that has included soldiers and equipment from units across post, as well as Fayetteville, Cumberland County and state law enforcement and rescue teams.
Fort Bragg Fire Department Battalion Chief Gerald Auch, the incident commander, said the terrain and fast water caused by recent heavy rains has made the search difficult.
Water levels of the Little River have dropped from 11.5 to 6 feet in the days since Gillespie went missing, authorities said.