The Daily (Prescott) Courier reported one firefighter survived the inferno with undetermined injuries.
The fatalities represented nearly the entire Prescott Fire Department, the newspaper said. Details of how the catastrophe occurred were not yet available.
A fire department spokesman told the newspaper the crew, known as the Granite Mountain Hotshots were battling the Yarnell Hill fire when disaster struck.
The Arizona Republic reported half the homes in Yarnell, a town of about 650 people, was burned by the blaze, which had blacked more than 2,000 acres and was running wild.