1st Battalion
August 1914 : in Trimulgherrey, India. Returned to UK and landed at Avonmouth on 10 January 1915.
10 January 1915 : attached to 87th Brigade, 29th Division.
5 February 1918 : transferred to 109th Brigade, 36th Division.
2nd Battalion
August 1914 : in Dover. Part of 12th Brigade, 4th Division.
6 December 1914 : transferred as GHQ Troops.
26 January 1915 : transferred to 5th Brigade, 2nd Division.
22 July 1915: transferred as Army Troops to Third Army.
8 November 1915 : transferred to 14th Brigade, 5th Division.
24 December 1915 : transferred to 96th Brigade, 32nd Division.
3 February 1918 : transferred to 109th Brigade, 36th Division.
3rd (Reserve) Battalion
August 1914 : in Omagh. Remained in Ireland until April 1918, then moved to England.
4th (Extra Reserve) Battalion
August 1914 : in Enniskillen. Remained in Ireland and England throughout the war.
Territorial Force
The Irish Regiments did not form battalions for the TF.
New Armies
5th (Service) Battalion
Formed at Omagh, August 1914, as part of K1. Became part of 31st Brigade, 10th (Irish) Division.
28 May 1918 : left the Division and moved to France.
19 July 1918 : transferred to 198th Brigade, 66th Division.
6th (Service) Battalion
Formed at Omagh, August 1914, as part of K1. Became part of 31st Brigade, 10th (Irish) Division.
2 May 1918 : left the Division and moved to France.
7 June 1918 : transferred to 43rd Brigade, 14th Division.
18 June 1918 : transferred to 103rd Brigade, 34th Division.
29 June 1918 : transferred to Lines of Communication.
16 July 1918 : transferred to 151st Brigade, 50th Division.
7th (Service) Battalion
Formed at Omagh, October 1914, as part of K2. Became part of 49th Brigade, 16th (Irish) Division.
23 August 1917 : amalgamated with 8th Bn to become 7/8th Bn.
22 April 1918 : reduced to cadre strength.
17 June 1918 : transferred to 102nd Brigade, 34th Division.
26 June 1918 : transferred to GHQ Troops, and re-established with men from 8th Rifle Brigade.
3 July 1918 : transferred to 89th Brigade, 30th Division.
8th (Service) Battalion
Formed at Omagh, October 1914, as part of K2. Became part of 49th Brigade, 16th (Irish) Division.
23 August 1917 : amalgamated with 7th Bn to become 7/8th Bn.
The following New Army battalions of this regiment were formed in 1914 from existing units of the Ulster Volunteer Force.
9th (Service) Battalion (County Tyrone)
Formed at Omagh, September 1914, from the Tyrone Volunteers (included two companies of Volunteers who had already joined the 5th and 6th Bns.). Became attached to 3rd Brigade, Ulster Division.
2 November 1914 : formation renamed 109th Brigade, 36th Division.
10th (Service) Battalion (Derry)
Formed at Omagh, September 1914, from the Derry Volunteers. Became attached to 3rd Brigade, Ulster Division.
2 November 1914 : formation renamed 109th Brigade, 36th Division.
21 January 1918 : disbanded in France.
11th (Service) Battalion (Donegal and Fermanagh)
Formed at Omagh, September 1914, from the Donegal and Fermanagh Volunteers. Became attached to 3rd Brigade, Ulster Division.
2 November 1914 : formation renamed 109th Brigade, 36th Division.
21 January 1918 : disbanded in France.
12th (Reserve) Battalion
Formed in Enniskillen in April 1915 as a local Reserve Bn.
Remained in Ireland until moving to England when absorbed by 3rd Bn in April 1918.
Other Battalions
13th (Service) Battalion
11 June 1918 : the 11th Garrison Guard Bn in France became the 13th (Garrison) Bn.
Attached to 119th Brigade, 40th Division.
13 July 1918 : renamed 13th (Service) Bn.
