The fire service said 55 firefighters with three teams and and 17 fire engines were sent to extinguish the fire on the island, located some 70 kilometers (43 miles) from Athens. A firefighting aircraft was used to battle the wildfire before dark.
Black smoke covered almost the entire airspace of Evia, the wildlife could be seen for miles, Greek broadcaster Ant1 reported.
A cement plant of the AGET Heraklis company and a power plant of the PPC state energy company were in the area of the fire but were not in danger. The fire had no threat to homes or any housing in the area, Aliveri Deputy Mayor Nikos Barakos told the broadcaster.
"The fire is in full swing, but, fortunately, no houses are in danger so far. However, the fire is burning in a very inaccessible area that the fire brigade cannot reach. We will be there all night until the fire is under control," he said.
The weather in Greece has been hot in recent days. There have been almost no massive wildfires in the country this year so far. Last year the country experienced one of its worst wildfire seasons in recent memory when over 2,400 acres burned compared to an average of 92.