Gardai have issued a warning following heavy rain throughout the county all day.
Dozens of roads have been flooded along their sides making driving hazardous.
There are reports of roads being partially flooded in Glenswilly, Ballyare, Ramelton, Lifford, Donegal Town and parts of Inishowen.
Gardai have urged motorists to slow down and not to drive at speed through flooded roads.
Further heavy rain is forecast in the coming days.