Croaghgorm or Bluestack () is a mountain in County Donegal, Ireland. It is the highest of the Blue Stack Mountains (or Croaghgorms) and the third-highest mountain in County Donegal. On 31 January 1944, during World War II, a Royal Air Force (RAF) Sunderland plane crashed on the mountain. Seven RAF crewmen from 228 Squadron were killed. Wreckage from the plane can still be seen on the mountain's slopes. A memorial plaque was unveiled in 1988. See also List of mountains in Ireland References Hewitts of Ireland Marilyns of Ireland Mountains and hills of County Donegal Mountains under 1000 metres Aviation accidents and incidents in Ireland