Donegal County Council has closed the R237 between Killea and Newtowncunningham to allow for essential repairs.
The road will remain closed until Friday, August 24.
There are diversions between Newtowncunningham/Letterkenny to Derry City and signage is in place to direct drivers from the R237/R265 junction towards Carrigans before moving onto the R236 to the Mullenan Road for Nixons Corner and Derry City.