Parts of the Florida Keys, the low-lying islands which bore the brunt of Hurricane Irma when the category-four storm struck on Sunday, are to re-open.
Entry is being restricted to residents and business owners as work continues to clear roads and check the state of bridges linking the islands.
Some 60% of homes in the state are still without power.
Irma, which has since rapidly weakened, is being linked to 10 deaths in the United States.
Six people died in Florida, three in Georgia and one in South Carolina.
The storm also left a trail of destruction in the Caribbean, where at least 37 people were killed.
French President Emmanuel Macron has arrived in the region and is to visit devastated French islands, while UK Foreign Secretary Boris Johnson is heading to the British Virgin Islands.
Both France and Britain have been criticised for not doing enough to help their nationals in overseas territories affected by the hurricane.
Dutch King Willem-Alexander spent Monday night on the Dutch side of St Martin, an island shared between France and the Netherlands.
"Even from the plane I saw something I have never seen before," the Dutch royal told the NOS public newscaster. "I have seen proper war as well as natural disasters before, but I've never seen anything like this".
"Everywhere you look there's devastation, you see the collapse," he added.
Florida Governor Rick Scott used the same word - "devastation" - after flying over the Keys on Monday.
"I just hope everybody survived," he said. "It's horrible what we saw. Especially for the Keys, it's going to be a long road.
"We saw a lot of boats washed ashore and we saw any, basically, any trailer park there overturned."
Thousands of people are believed to have ignored calls to evacuate last week, and clung on in the dangerously exposed islands during the storm.
However, Governor Scott added: "I didn't see the damage I thought I would see." Storm surges had turned out to be "not as bad as we thought", he said.
Teams are still working to clear Highway 1, the road connecting most of the inhabited islands, and bridge inspections are continuing.
People with authorisation are being allowed into the towns of Key Largo, Tavernier and Islamorada from 07:00 (11:00 GMT), the authorities in Monroe Country said.
They were warned that services on the islands were limited: most areas were still without power and water, mobile phone signals were patchy and most petrol stations were still closed.
The US aircraft carrier Abraham Lincoln has arrived off Florida and other navy ships are due in the area on Tuesday to help distribute food to the Keys and evacuate residents.
Relief in Miami
Other parts of the state escaped the storm lightly compared to the Caribbean islands.
"The storm surge flooding in Miami is a mere fraction of what would have happened if the core of the storm had been further east," Rick Knabb, former director of the National Hurricane Center, said in a tweet.
Miami's Mayor, Carlos Gimenez, was relieved the damage was no worse.
"We were spared the brunt of this storm," he said. "We came out much better than other parts of the state and we have to thank God for that."
Returning to her home in Miami's Little Haiti neighbourhood, evacuee Melida Hernandez, 67, found her home split down the middle by a tree.
"I wanted to cry, but this is what it is, this is life," she told Reuters news agency.
President Donald Trump has released emergency federal aid for Florida, describing the hurricane as a "big monster".
The storm was downgraded as it moved north towards Atlanta, Georgia, with maximum sustained winds of 35mph (56km/h) recorded, the National Hurricane Center (NHC) said in a statement.
Which areas were hit before Florida?
Irma has been the most powerful Atlantic storm in a decade, and caused widespread destruction on several Caribbean islands:
- Cuba: At least 10 people were killed by the storm on the island, officials say. Three quarters of the population are without power
- St Martin and St Barthelemy: Six out of 10 homes on St Martin, an island shared between France and the Netherlands, are now uninhabitable, French officials say. Nine people had died and seven were missing in the French territories, while four are known to have died in Dutch Sint-Maarten
- Turks and Caicos Islands: Widespread damage, although extent unclear
- Barbuda: The small island is said to be "barely habitable", with 95% of the buildings damaged. One death has been confirmed
- Anguilla: Extensive damage with one person confirmed dead
- Puerto Rico: More than 6,000 residents of the US territory are in shelters and many more without power. At least three people have died
- British Virgin Islands: Widespread damage reported, and five dead
- US Virgin Islands: Damage to infrastructure was said to be widespread, with four deaths confirmed
Another hurricane, Jose, has been weakening over the western Atlantic, with swells due to affect parts of Hispaniola (the island split into Haiti and the Dominican Republic), the Bahamas, and the Turks and Caicos Islands, later this week.