Authorities evacuated about 300 homes in north Florida as two fires totaling 130,000 acres continued to rage on the Georgia-Florida border.
Florida officials warned that they might soon need help if the blazes grow out of control.
Officials prepared to evacuate staff in Georgia's Okefenokee National Wildlife Refuge as the largest recorded blaze in state history neared part of the park. The 107,000-acre blaze was nearing part of the park that has served as a fire crew command post. Another fire in southern Georgia covered 40,000 acres and crossed the Florida border.
The smaller fire crossed into Florida on Tuesday and was threatening Taylor, a small town with one store and no cell phone coverage, said Baker County Sheriff Joey Dobson.
Florida is already under a fire-induced state of emergency, with high wind and tinder-dry conditions spawning some 210 blazes over 43,500 acres. No injuries have been reported. Only a handful of houses and other buildings have been destroyed or damaged.
Florida officials issued a ban Tuesday on yard waste burning.
Meanwhile, a wildfire in northern Minnesota has already destroyed 40 homes and buildings, and brush fires in Georgia and northern Florida have charred more than 200 square miles.
In the Midwest, a wildfire near the Canadian border in northeastern Minnesota had burned 16,266 acres since it was spotted Saturday. It destroyed around 40 buildings, including multimillion-dollar homes, and forced more than 100 people to evacuate.
Authorities said they believe it started at a campsite just outside the Boundary Waters Canoe Area.
"There are some houses up there where all there is left is the foundation," said Leif Lunde of the Cook County Sheriff's Department. No injuries were reported, but Lunde said about 30 of the burned buildings were homes or cabins.