Truagh (; ) is a barony in the north of County Monaghan in Ireland.
Trough or Truagh is known in Irish as An Triúcha (Old Irish trÃÂcha cét, "cantred").
Trough is found in north County Monaghan, south of the Ulster Blackwater.
Trough barony is bordered to the south by Monaghan, County Monaghan; to the northwest by Clogher, County Tyrone; and to the northeast by Lower Dungannon, County Tyrone.
The Mac Kenna were chiefs of Trough. O'Clerkin is also noted here.
Below is a list of settlements in Trough barony: