Four members of the group were rescued and taken to hospital with non-life threatening injuries after the Dan River tragedy in North Carolina, said Rockingham County Emergency Services Director Rodney Cates.
All nine people were doing tubing – an activity that involves crossing water on inflatable rings.
They crossed the Duke Energy Dam in the city of Eden on Wednesday around sunset, Cates said.
He added that the dam is approximately 2.5m (8ft) high.
Mr Cates also said that a Duke Energy employee who had seen some of the tubers called 911 to report what was going on.
Rockingham County Sheriff Sam Page identified those rescued as Reuben Villano, 35 – and children Eric, 14, and Irene, 18.
The fourth person rescued was Karlos Villano of LaPorte, Indiana.
The sheriff’s office named the deceased as Bridish Crawford, 27, Antonio Ramon, 30, and Sophie Wilson, 14.
The two missing are Teresa Villano, 35, and Isiah Crawford, 7.
Search teams scoured the Dan River on Friday to try to locate those who have not been found.
The search will resume on Saturday, Cates said.
Boats and helicopters were used for searches in Rockingham County, north of Greensboro, along the Virginia state border.
Mr Cates said those rescued spent the night floating in the water near the dam before they were found hanging from their tubes.
He said they managed to stay afloat for around 19 hours, describing them as “very, very tired” when they were found.
First responders said the survivors were caught in flowing water near the dam when they were found, according to traffic records from scanners on broadcastify.com.
Rescuers could be overheard by public safety radio ordering boats and other whitewater rescue equipment in the area shortly after the 911 call around 3:15 p.m. Thursday.
“We take a call on the Dan River at the dam near the Duke Energy plant. The appellant advises that five tubers… have crossed the dam, ”said one person.
A rescuer says on the recording that some of the tubers were stuck near the dam due to the attraction of the water flowing over them.
“They’re on this side… at the abutment of the dam. And they’re all caught up in the pull. If you can come… we can probably pull them off pretty well, hopefully, ”the rescuer can be heard.
Mr Cates told reporters that debris and rocks in the river can pierce tubes or rafts, so it is important for people to wear life jackets. He said it was not clear if any of the nine were wearing such a jacket.
Mr Cates said it was not unusual for people to float down the river on tubes or rafts in the area, but most come out and walk around the dam, which is marked with signs.