The fire grew from about 3,000 acres Wednesday morning to about 5,000 acres in the afternoon, said Annaleasa Winter, a spokeswoman for the Florida Division of Forestry,
As a precaution, the Bradford County Emergency Management Center evacuated about 500 people from areas south and east of the blaze, much of which is burning in inaccessible areas of the Santa Fe swamp, she said.
No injuries have been reported and no homes or structures have been damaged. Hampton is about 50 miles southwest of Jacksonville.
Additional tractors were being brought in Wednesday and fire crews would be working to build lines and protect homes and buildings in the area. Early Wednesday, the fire was 10 to 20 percent contained, she said.
In another north Florida blaze, more than 100 firefighters in the remote John Bethea State Forest, north of Baxter near the Georgia border, gained ground on a blaze covering nearly 3,000 acres. The fire was 75 percent contained by late Tuesday with the help of a half-inch of rain on part of it, according to Gene Madden, a spokesman with the forestry division.
Winter said crews and tractors from that fire were being moved to the Santa Fe swamp blaze.
Meanwhile in South Florida, the Alligator Alley portion of Interstate 75 was reopened about three hours after smoke from a 3,000-acre Everglades brush fire reduced visibility in the area to zero, forcing the road to be closed in both directions.
I-75, which crosses south Florida from State Road 29 in Collier County to U.S. 27 in Broward County, reopened shortly before midnight Tuesday, after winds pushed the fires north, the Florida Highway Patrol said.
Though flames around the highway had died down by early Wednesday morning, blazes continued to burn elsewhere, and troopers were monitoring the area, said FHP Lt. Roger Reyes.
``They're sporadic all over out there,'' he said of the fires. ``It depends on Mother Nature and the shift of the wind.''
The Alley is one of two east-west routes crossing the Florida Everglades. The other, Tamiami Trial between Miami and Naples, is a two-lane road for much of the way.
Meanwhile, a wildfire that consumed 1,300 acres in southwest Florida, prompting nearby Florida Gulf Coast University to cancel classes on Tuesday, was 100 percent contained, said Gerry Lacavera, wildfire mitigation specialist for the state Division of Forestry.
At one point over the holiday weekend, the fire got within 40 feet of the campus, and the smoke was so thick that an assistant campus fire chief couldn't locate his truck in daylight, said Robert Harris, the campus police chief.
The university reopened Wednesday.