Arkansas state police say searchers have found the body of the last person known to have gone missing when a flash flood swept through a popular campground last Friday.

Spokesman Bill Sadler said searchers found the body of a 20th victim Monday morning and that crews would continue scouring the rugged wilderness in and around the Albert Pike Recreation Area, a 54-unit campground in the Ouachita National Forest.

Sadler did not say whether the body was that of an adult or child. Dozens of people were feared missing after the flood, but authorities on Sunday had narrowed their search to just one remaining person.

On June 11, floodwaters that rose as swiftly as 2½ metres an hour tore through the campground, which was packed with vacationing families.

Heavy rains caused the normally quiet Caddo and Little Missouri rivers to rise above their banks during the night.