The forest near Schierke in the Harz National Park continued to burn on Friday morning.
According to previous knowledge, an area of 37 hectares was affected, said the Harz rescue control center.
At the moment, however, no specific locations are directly endangered.
However, the spread of the fire must be checked again, said a spokesman for the control center.
The forest fire broke out on Thursday.
The smoke was visible from afar, as the Wernigerode volunteer fire department announced on Facebook.
During the night, the fire brigades had withdrawn somewhat and were only at the scene of the fire with the most necessary emergency services.
The fight against the flames should be stepped up again on Friday morning, with several helicopters and the support of fire brigades from surrounding counties.