This brigade in the unit formation listed here existed on the first critical date 11 July 1921 only. Prior to the second critical date of 1 July 1922 the units listed here were re-formed into different formations. The first three companies listed of the 1 (Castlegar) Battalion were transferred to the 2 Brigade, 1 Western Division and the other four companies listed of the 1 (Castlegar) Battalion were transferred to the 3 Battalion, North Galway Brigade, 2 Western Division. The Claregalway Company of the 2 Battalion was transferred to the 5 Battalion, 2 Brigade, 1 Western Division and the other three companies listed were transferred to the 2 Battalion, North Galway Brigade, 2 Western Division. The 3 (Headford) Battalion was transferred to the 2 Battalion, North Galway Brigade, 2 Western Division. 1 (Castlegar) Battalion: Unit strength on 11 July 1921 was 469 all ranks.The companies of the 1 Battalion were located as follows:  Castlegar,  Galway City,  Derrydonnell,  Newcastle,  Cregmore,  Cussaune,  and Monivea.2 (Claregalway) Battalion: Unit strength on 11 July 1921 was 154 all ranks.The companies of the 2 Battalion were located as follows:  Claregalway,  Annaghdown A,  Annaghdown B,  and Kilcoona.3 (Headford) Battalion: Unit strength on 11 July 1921 was 135 all ranks.The companies of the 3 Battalion were located as follows: Clooneen,  Claran,  and Caherlistrane.