The Road Safety Authority figures, which are based on population rank Donegal the third most dangerous behind Kerry and Cork.
The figures show that the national average of deaths on Irish roads per county last year was 41 per one million people.
Donegal is much higher than the average, with the equivalent of 81 deaths per one million people, twice the national average.
The figures have led to concerns that the reduction in deaths and serious injuries on Irish roads in recent years are in danger of being lost.
The RSA has also released figures on drivers disqualified for have 12 points or more on their license. In 2012, 7 drivers lost their license in Donegal, that fell to 2 last year.