South Boston Police Chief G.M. Reed said the fire at Planter's Warehouse prompted the closure of a portion of Wilborn Avenue, the main street through downtown, for at least a day.
Firefighters from the county's volunteer departments, as well as personnel from Danville and Roxboro, N.C., joined the town department in fighting the blaze, Reed said.
Authorities said they did not immediately know what caused the blaze.