The 16th (Irish) Division was a division of the New Army, raised in Ireland from the Irish National Volunteers in September 1914 as part of the K2 Army Group. In December 1915, the division moved to France, joining the British Expeditionary Force (BEF), under the command of Irish Major General William Hickie, and spent the duration of the First World War in action on the Western Front. Following enormous losses at the Somme, Passchendaele and Ypres, the Division required a substantial refit in England between June and August 1918, which involved the introduction of many non-Irish battalions.

Unit history:

The Division began forming towards the end of 1914 after Irish recruits in the early days of the war from England and Belfast first filled the ranks of the 10th (Irish) Division before being assigned to the 16th Division, formed around a core of the Irish National Volunteers. Initial training began in Ireland at Fermoy and Buttevant, when it was moved to Aldershot Barracks in England for more intensive training in September 1915. After thirteen weeks, the unit was deployed to Etaples, France, where they left on December 18 for the front at the earlier Battle of Loos salient.

At Loos they got their introduction to trench warfare in January and February 1916, and suffered greatly in the Battle of Hulluch, April 27-April 29, 1916. They raided German trenches all through May and June, and in late July they were moved to the Somme Valley where they were intensively engaged in the Battle of the Somme.

The Division was critical in the capture of the towns of Guillemont and Ginchy, though they suffered massive casualties.

In early 1917, the division took a major part in the Battle of Messines alongside the 36th (Ulster) Division, due to both their recognition and reputation. Their major actions ended in the summer of 1917 at the Battle of Passchendaele after moving under General Hubert Gough's Fifth Army command. He had little regard for the Irish and in July 1917 during the Third Battle of Ypres, although both divisions were totally exhausted after 13 days of moving heavy equipment under heavy shelling he ordered their battalions advance to the east of Ypres through deep mud towards well fortified German positions left untouched by totally inadequate artillery preparation. By mid August the 16th (Irish) had suffered over 4,200 casualties and the 36th (Ulster) had suffered almost 3,600 casualties, or more than 50% of their numbers, which General Haig was very critical of him for "playing the Irish card".

In early 1918, the division held an exposed position at Ronssoy during the German Spring Offensive. They suffered heavy losses here and during the retreat which followed, also under Gough's command, for which he was dismissed. They helped finally halt the German attack at the Battle of Hamel. The 16th were returned to England on 14 June 1918 for "reconstitution". The Conscription Crisis of 1918 in Ireland meant that no Irish conscripts could be raised. The "16th Division" which returned to France on 27 July contained 5 English Battalions, 2 Scottish Battalions and 1 Welsh Division. The only original Battalion left was the 5th Royal Irish Fusiliers.

Formation:

47th Brigade
8th (Service) Battalion, Royal Munster Fusiliers (New Army) (disbanded November 1916)
6th (Service) Battalion, Royal Irish Regiment (disbanded 1922)
7th (Service) Battalion, Leinster Regiment; (disbanded February 1918)
6th (Service) Battalion, Connaught Rangers (until June 1918)
1st (Service) Battalion, Royal Munster Fusiliers (from November 1916 until April 1918)
18th (Service) Battalion Welsh Regiment (2nd Glamorgan), (from May 1918)
14th (Service) Battalion, Leicestershire Regiment (from June 1918)
9th (Service) Battalion, Black Watch (from July 1918)
2nd (Service) Battalion, Leinster Regiment (from February 1918 until April 1918)
47th Machine Gun Company Joined 28 April 1916, moved to 16th Battalion MGC 9 March 1918
48th Brigade
9th (Service) Battalion, Royal Munster Fusiliers (New Army) (disbanded May 1916)
7th (Service) Battalion, Royal Irish Rifles (until August 1917)
8th (Service) Battalion, Royal Dublin Fusiliers (merged with 9th Battalion October 1917)
9th (Service) Battalion, Royal Dublin Fusiliers (merged with 8th Battalion October 1917)
1st (Service) Battalion, Royal Munster Fusiliers (from May 1916 until November 1916)
1st (Service) Battalion, Royal Dublin Fusiliers (from October 1917 until April 1918)
2nd (Service) Battalion, Royal Munster Fusiliers (from February 1918 until May 1918)
22nd (Service) Battalion, Northumberland Fusiliers (from June 1918)
18th (Service) Battalion, Cameronians (Scottish Rifles) (from July 1918)
11th (Service) Battalion, Royal Irish Fusiliers (from June 1918 until August 1918)
5th (Service) Battalion, Royal Irish Fusiliers (from August 1918)
10th (Service) Battalion, Royal Dublin Fusiliers (from June 1917, disbanded February 1918)
48th Machine Gun Company Joined 28 April 1916, moved to 16th Battalion MGC 9 March 1918

The 8th and 9th Battalions of the Royal Dublin Fusiliers combined to form the 8/9th Battalion in October 1917 which was subsequently disbanded in February 1918.
49th Brigade
7th (Service) Battalion, Royal Irish Fusiliers (merged with 8th Battalion October 1916, disbanded February 1918)
8th (Service) Battalion, Royal Irish Fusiliers (merged with 7th Battalion October 1916, disbanded February 1918)
7th (Service) Battalion, Royal Inniskilling Fusiliers (merged with 8th Battalion August 1917)
8th (Service) Battalion, Royal Inniskilling Fusiliers (merged with 7th Battalion August 1917)
2nd (Service) Battalion, Royal Irish Regiment (from October 1916 until April 1918)
7th (Service) Battalion, Royal Irish Rifles (from August 1917 until October 1917)
7th (Service) Battalion, Royal Irish Regiment (South Irish Horse) Battalion,(from October 1917 until July 1918)
34th (Service) Battalion, The London Regiment (County of London) Battalion (from June 1918)
6th (Service) Battalion, Somerset Light Infantry (from July 1918)
18th (Service) Battalion, The Gloucestershire Regiment (from July 1918)
49th Machine Gun Company Joined 29 April 1916, moved to 16th Battalion MGC 9 March 1918

The 7th and 8th Battalions of the Royal Irish Fusiliers combined to form the 7/8th Battalion in October 1916 which was subsequently disbanded in February 1918. The 7th and 8th Battalions of the Royal Inniskilling Fusiliers combined to form the 7/8th Battalion in August 1917 which was subsequently disbanded in February 1918.