Greencastle (from Irish An Caisleán Glas 'the green house')[1] is a hamlet in County Tyrone, Northern Ireland.
It is within the townland of Sheskinshule[2] (from Irish Seisceann Siúil).
[3] The village sits at a crossroads in the foothills of the Sperrin Mountains with the Owenkillew and Owenreagh rivers running nearby.
It had a population of 153 people in the 2001 Census.
In 2012, a Real IRA training camp was discovered in the hamlet, leading to four people jailed for terrorism offences in 2014.