The person is believed to have escaped serious injury but was taken to Letterkenny General Hospital for treatment.
The road at Dreenan Bridge in Ballybofey has re-opened after being closed for a time after the incident earlier this evening.
Gardaí say they are investigating the circumstances surrounding the incident.
The accident is the latest in a series of incidents in Co Donegal in recent days.
Ten people have lost their lives on the county’s roads this year – one more for than the whole of 2013.
Garda Inspector Michael Harrison has pleaded with motorists to drive with extra care as heavy rain and showers are expected over the next week.
It’s understood a number of extra traffic patrols are on duty over the next few days as Gardaí bid to stamp out poor driving.