Authorities have shut down Union Church Road in Vass as a safety measure while firefighting operations continue.
When it broke out in July, the Museum Fire charred three square miles and forced the evacuation of two dozen homes near Flagstaff, Arizona.
Some 44,000 troops will be available for "unprecedented" operations to put out the fires that have swept the region.
A government monitoring agency said Brazil has seen 74,155 fires as of Tuesday, an 84 percent increase over last year.
The Mountain Fire's massive plume of smoke reached more than 10,000 feet into the air and was detected on National Weather Service radar.
A wildfire has destroyed a large part of the woodland that inspired the children's series "Winnie-the-Pooh" in southern England.