The eye of Hurricane Irma has hit mainland Florida, just south of Naples, amid warnings of storm surges as high as 15ft.
The hurricane has been downgraded to a category 3 storm, but made landfall on Marco Island off Florida’s west coast with winds of up to 120mph.
More than 1 million homes across Florida are without power, and parts of the city of Miami are under water.
Irma has devastated parts of the Caribbean, killing at least 27 people.
Some 6.3 million people in Florida had been told to evacuate.
Irma hit Marco Island at 15:35 local time. It had earlier barreled through the Florida Keys, a chain of low-lying islands to the south.
The whole of the southern tip of Florida has seen high winds, driving rain and storm surges,
About 2ft of water has been seen in Miami’s financial district, where one major street resembled a river, but the worst damage is expected on the west coast.
President Donald Trump described hurricane Irma as a “big monster”. He praised the federal agencies involved with the storm and said he would go to Florida “very soon”.