Fire units from Dornoch, Tain, Lairg, Balintore, Inverness, Dingwall and two from Invergordon have been at the scene since the early afternoon.
A water carrier was also sent to the area from Inverness.
A spokesman for the Scottish Fire and Rescue Service has now confirmed the blaze is under control.
The spokesman added: “The fire service will remain at the location during the night to monitor the situation.
“It is possible that should winds gust, the fires may re-ignite and appear dramatic against the backdrop of darkness however, the fire service will continually assess the situation throughout.”