This brigade was located in Co. Monaghan and consisted of three battalions known as the Monaghan, Ballybay, and Carrickmacross Battalions. The battalions were known as the 2, 4 and 5 battalions before the setting up of the 5 Northern Division circa June 1921. When the division was set up the numbering was retained.
2 Monaghan Battalion: Unit strength on 11 July 1921 was 356 all ranks, and the strength on 1 July 1922 was 264 all ranks. The companies of the 2 Battalion were located as follows: Ardaghey, Monaghan, Annyalla, Clontibret, Tyholland, Threemilehouse, Corcaghan, Smithboro and Middleton.
4 Ballybay Battalion: Unit strength on 11 July 1921 was 356 all ranks, and the strength on 1 July 1922 was 155 all ranks. The companies of the 4 Ballybay Battalion were located as follows: Latton, Ballybay, Tullycorbett, Doohamlet, Rockcorry, Castleblaney, Loughleigh and Carrickatee.
5 Carrickmacross Battalion: Unit strength on 11 July 1921 was 313 all ranks, and the strength on 1 July 1922 was 165 all ranks. The companies of the 5 Battalion were located as follows: Carrickmacross, Magheracloone Upper, Killanny, Inniskeen, Bawn, Corduff, Donaghmoyne, Lisdoonan, Magheracloone Lower, Broomfield and Mileriver.