This brigade – in the unit formation set out here – was not formed by the first critical date 11 July 1921 and all data (with the exception of the ASU) is for the period 1 July 1922 only.
On 11 July 1921 the 1, 2, 3, 4 Battalions were part of the Sligo Brigade, 2 Western Division.

1 Battalion: Unit strength on 1 July 1922 was 701 all ranks. The companies of the 1 Battalion were located as follows: Tubercurry, Cloonaughill, Cully, Curry, Cashill, Cloonacool, Tourlestrane, Kilmactigue, Mullinabreena, Achonry, Moylough and Glenesk.
2 Battalion: Unit strength on 1 July 1922 was 246 all ranks. The companies of the 2 Battalion were located as follows: Collooney, Coolaney, Ballisodare, Carrickbanagher, Ballygawley, Ballinacarrow, Screen & Dromard and Templeboy.
3 Battalion: Unit strength on 1 July 1922 was 462 all ranks. The companies of the 3 Battalion were located as follows: Ballymote, Keash, Culfadda, Killavil, Bunninadden, Emlaughton, Kilcreevan, Ballinafad, Ballinaglough and Derroon.
4 Battalion: Unit strength on 1 July 1922 was 128 all ranks. The companies of the 4 Battalion were located as follows: Gurteen, Cloonloo, Monasteraden and Edmondstown.

Active Service Unit: source gives a strength of 198 all ranks effective with the 4 Brigade Active Service Unit for the period 11 July 1921. Personnel were attached to the A.S.U. from the battalions of the brigade and the file contains listings of persons concerned.