The woodlands near Ramelton are specially protected under national and European laws.
But visitors to the 30-hectare site have often been put off by the deep muddy paths around the forest.
Now however the National Parks and Wildlife Service are laying new paths and carrying out new conservation work there.
The move has been welcomed by local TD Joe McHugh who had lobbied for the upgrade.
“Ballyarr Wood is not just important from a conservation point of view in Donegal but is recognised nationally as one of the country’s finest oak woods,” said Deputy McHugh.
“I know it means a great deal to people in the area who use it often and I’m delighted this work is now underway to make it more accessible.”