The brutal attack happened in the early hours of yesterday morning between Milford and Ramelton.
The woman was attacked at a house at Aras Ui Domhnaill at around 7am.
The woman was rushed to Letterkenny General Hospital but it is understood her injuries are not life-threatening.
A 30 year old man was arrested at the scene and was taken to Milford Garda station for questioning.
Gardai sealed off the scene of the attack and carried out a full forensic examination.
The man was still being questioned under Section 4 of the Criminal Justice Act tonight.
A spokesman for the Garda press office confirmed to Donegaldaily.com: “Gardai attended the scene of an assault at Aras Ui Domhnaill at approximately 7.30am.
“A male (30 years) was arrested at the scene and is currently being detained at Milford Garda station.
“During the assault a female was injured and attended Letterkenny General Hospital for treatment. Her injuries are described as not life-threatening,”
In another two unrelated incidents, a Garda was beaten and a man was stabbed within the vicinity of the village of Ramelton over the weekend.