The Willow fire crossed State Route 87 on Wednesday night after firefighters conducted burnout operations and built lines between the road and the blaze for the past few days.
Firefighters put out the fires Wednesday night and continued to conduct burnout operations along the highway Thursday.
Small communities near the highway that include Deer Creek, Rye and Gisela were not considered threatened, said Carrie Templin, a spokeswoman for the crew battling the fire.
State Route 87 was closed between the junction at State Route 188 and the Bush Highway.
The closure prevents people from driving to Payson or Phoenix via State Route 87, or the Beeline Highway.
The lightning-caused Willow fire, which started June 24, was considered 25 percent contained by Thursday.
Firefighters believe they have successfully defended the communities of Payson, Pine and Strawberry against the growing fire, fire officials said.
Nearly 770 firefighters continued Thursday to work on the fire, which has cost $6.8 million to fight.
SAN CARLOS, Ariz. (AP) -- Firefighters battled a 230-acre wildfire burning in steep and rugged terrain about 30 miles east of here on the San Carlos Apache Indian Reservation.
The Military fire, which was burning oak brush, ponderosa pines and juniper trees, was 15 percent contained by Thursday, said Bob Dyson, a spokesman for the crew fighting the blaze.
No structures were threatened though the fire was threatening habitat for endangered spotted owls.
About 200 firefighters worked to put out hot spots on the fire, which was sparked by lightning Tuesday.
Full containment was expected by Saturday, Dyson said.