The hurricane was also deadly, killing five people.
A mother and baby were killed when a tree fell on a house, according to a tweet from Wilmington police. The father was taken to the hospital to be treated for injuries.
A woman in Hampstead, in Pender County, died of an apparent heart attack after emergency crews could not clear debris to get to her.
The centre of the hurricane made landfall near Wrightsville, North Carolina, at 7.15am local time.
Farther up the coast, in New Bern, about 150 people waited to be rescued from flooding on the Neuse River, WXII-TV reported.
Trump, who plans a visit to the region next week, tweeted his "deepest sympathies and warmth" to the families and friends of those who had lost their lives.
Buildings were torn apart by 90mph winds and hundreds of people were trapped by high water as the Category 1 storm settled in for what could be an extraordinarily destructive drenching.
"The wind was so hard, the waters were so hard, that trying to get out we got thrown into trailers". The town of Oriental, North Carolina, got more than 20 inches (50 centimetres) just a few hours into the deluge.
But the size of the storm meant the path didn't really matter. Data supplied by the US National Hurricane Center suggest that the point of landfall was near 34.2 N, 77.4 W. Florence brought 1-minute maximum sustained winds to the region of around 148 km/h (92 mph).
By early Friday morning, more than 100 people who did not heed the warnings to evacuate were rescued from their homes. He said that only 300 of the city's 22,000 residents have power as of Friday afternoon.
The storm has caused power outages, flooding and structural damage to several homes and businesses in North and SC.
Americans invited to 'shoot guns at Hurricane Florence'
An estimated 250,000 more people from the northern Outer Banks were due to be sent to higher ground starting Tuesday at midday. Many people in the Southeast and Mid-Atlantic probably have not experienced a storm of the potential magnitude of Florence.
Its storm surge and the prospect of 1 to 3 1/2 feet of rain were considered a bigger threat than its winds, which had dropped off from an alarming 140 miles per hour - Category 4 - earlier in the week.
The Triangle is under a flash flood warning until 8 p.m. Sunday.
The worst of the storm's fury had yet to reach coastal SC, where emergency managers said it was not too late for people to get out.
Emergency officials encourage all residents to stay inside for safety reasons.
"Hurricane Florence is powerful, slow and relentless", Cooper said. "It's an uninvited brute who doesn't want to leave".
Forecasters said Florence's surge could cover all but a sliver of the Carolina coast under as much as 11 feet of sea water.
The hurricane was "wreaking havoc" and could wipe out entire communities as it makes its "violent grind across our state for days", the governor said.
Travel is extremely hazardous because of storm surge, Trogdon said, and will only get worse. He called the rain an event that comes along only once every 1,000 years.
Nearly 20 000 people had taken refuge in 157 emergency shelters, Cooper said.
Ominously, forecasters said the onslaught on the North Carolina-South Carolina coast would last for hours and hours because the hurricane had come nearly to a dead stop at just 3 mph (6 kph) as of midday.
Others who chose to stay at home perhaps regretted their decision. The city said two Federal Emergency Management Agency teams were working on swift-water rescues, and more were on the way. "You may need to move up to the second story, or to your attic, but WE ARE COMING TO GET YOU".