Shortly before 9pm on Sunday, Gardaí and Emergency Services were called to the scene of a single car crash on a local road near Magheraroarty, Gortahork.
The occupants of the car, four men understood to be aged in their 20s, were pronounced dead at the scene a short time later.
The scene is preserved for a technical examination and local diversions are in place.
Garda forensic collision investigators are currently at the crash site and the local Coroner has been notified.
Gardaí investigating the incident are appealing for witnesses to contact them. Anyone with information is asked to contact Milford Garda Station on 074-9153060 or the Garda Confidential Line 1800 666 111.
The investigation is ongoing and further updates will follow.