An Chéad Chathlán Coisithe (English: The First Infantry Battalion) was established as an Irish language speaking unit in Galway in 1924. The role of An Chéad Chathlán Coisithe was seen as very important as far as the status and use of the first official language (Irish) of the State was concerned.^[2] All the armed forces units except An Chéad Cathlán functioned exclusively through the medium of the State's second official language (English). In modern times, the use of Irish as a working language in Óglaigh na hÉireann would appear to have been abandoned, even in An Chéad Chathlán. The then Minister for Defence, Mr O'Toole (on 4 December 1986) presented details regarding the recruitment of native Irish speakers to An Chéad Chathlán. These details show that no recruit from a Gaeltacht area was enlisted into the battalion in 1983.^[3] Under the 'Defence Forces [sic] Scheme' 2006-2009 ( under Section 11 of the Official Languages Act 2003) Óglaigh na hÉireann have undertaken to improve the delivery of services in Irish to the public. The aim of the Official Languages Act 2003 is to increase and improve in an organised manner over a period of time the quantity and quality of services provided for the public through Irish by public bodies. The legislation intends to create a space for the language in public affairs in Ireland.,^[4]

It is noteworthy that the term public means individuals, legal persons and corporate bodies. lrlsh air corp are acting in a capacity which is representative of the State, Government or, where appropriate, contractor personnel, providing a service on behalf of Óglaigh na hÉireann.^[5] Consequently, persons who fulfil official functions of a public nature, even though they are legal persons, do not come within the meaning of the word public when they are fulfilling those official functions.

Only in Gaeltacht areas is there an onus on Óglaigh na hÉireann to use Irish as the working language of the force. Section 13(2)(e) of the Official Languages Act states that a Public Body shall " ensure that the Irish language becomes the working language in its offices in the Gaeltacht not later than such date as may be determined by it with the consent of the Minister."^[6] There are no permanently manned Barracks or Posts of Óglaigh na hÉireann in Gaeltacht regions, "there are, however, training centres of na hÓglaigh Chúltaca (Reserve elements) manned on a part-time basis in the following locations: Carna, Maigh Cuilinn, An Cheathrú Rua, An Daingean." Under its agreed Language Scheme Óglaigh an hÉireann "will ensure that, by 2012, Irish will become the working language of these locations."

The Ceremonial Military Guard (Garda Míleata Searmanais) of the Irish Defence Forces is a guard of honour unit drawn from every battalion in the corps. It is also known as the Garda Onóra (Guard of Honour in English). It is inspected by the President of Ireland, Taoiseach or visiting military and political dignitaries. Personnel of the guard carry Steyr AUG rifles.^[7]

The Defence Forces participate in the State ceremonial connected with:

• Presidential Inaugurations
• Presidential State Visits Abroad
• State Visits to Ireland by Heads of State and Government
• Presentation of Credentials by Ambassadors
• 1916 Commemoration Ceremonies
• State Funerals
• National Day of Commemoration
• Easter Parade
• Changing of the Guard on Merrion Square
• National Famine Commemoration

The guard wears the Service Dress (SD) on ceremonial occasions. The Ceremonial Military Guard also takes part in the Changing of the Guard at Merrion Square park in Dublin.^[8]

Current units of the Infantry Corps:

• An Chéad Chathlán Coisithe
• 3 Infantry Battalion
• 6 Infantry Battalion
• 7 Infantry Battalion
• 12 Infantry Battalion
• 27 Infantry Battalion
• 28 Infantry Battalion
• 1 Mechanised Infantry Company
• Infantry School
  • Officer Training Wing
  • Non Commissioned Officers Training Wing
  • Infantry Weapons Wing

Disestablished units:

• 2 Infantry Battalion (1924-2012)
• 4 Infantry Battalion (1924-2012)
• 5 Infantry Battalion (1924-2012)
• 6 Infantry Battalion (1924-1929) - (Current 6 Inf Bn established in 1940)
• 7 Infantry Battalion (1924-1929, 1940-1959) - (Current 7 Inf Bn established in 2012)
• 8 Infantry Battalion (1924-1929, 1940-1946)
• 9 Infantry Battalion (1924-1929, 1940-1946)
• 10 Infantry Battalion (1924-1929, 1940-1946)
• 11 Infantry Battalion (1924-1929, 1940-1946)
• 12 Infantry Battalion (1924-1929) - (Current 12 Inf Bn established in 1940)
• 13 Infantry Battalion (1924-1929, 1940-1959)
• 14 Infantry Battalion (1924-1928, 1941-1946)
• 15 Infantry Battalion (1924-1928, 1941-1946)
• 16 Infantry Battalion (1924-1928, 1941-2005)
• 17 Infantry Battalion (1924-1927, 1941-1946)
• 18 Infantry Battalion (1924-1927, 1941-1946)
• 19 Infantry Battalion (1924-1927, 1941-1946)
• 20 Infantry Battalion (1924-1927, 1941-1946)
• 21 Infantry Battalion (1924-1927, 1941-1946)
• 22 Infantry Battalion (1924-1927, 1941-1946)
• 23 Infantry Battalion (1924-1927, 1941-1946)
• 24 Infantry Battalion (1924-1927, 1941-1946)
• 25 Infantry Battalion (1924-1927, 1941-1946)
• 26 Infantry Battalion (1924-1927)
• 27 Infantry Battalion (1924-1927) - (Current 27 Inf Bn established in 1973)
• 29 Infantry Battalion (1976-1998)
• 30 Infantry Battalion (1977-1998)
• 31 Infantry Battalion (1941-1946)

Disestablished reserve units:

• 32 Reserve Infantry Battalion (Made up of 14, 15 and 22 Battalions of the FCA) (2012)
• 33 Reserve Infantry Battalion (2012)
• 34 Reserve Infantry Battalion (2012)
• 51 Reserve Infantry Battalion (2012)
• 56 Reserve Infantry Battalion (2012)
• 58 Reserve Infantry Battalion (2012)
• 62 Reserve Infantry Battalion (made up of 20 and 21 Battalions of the FCA) (2012)
• 65 Reserve Infantry Battalion (made up of 7 FCA Battalion) (2012)
• 67 Reserve Infantry Battalion (2012)

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  Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, reviews the Irish Honor Guard at Brugha Barracks in Dublin, Aug. 31, 2012.
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  Guard Ceremony, Merrion Square
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  State visit President of Mozambique
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  A Mowag Piranha of the 3rd Infantry Battalion at the 2006 Easter parade Dublin.

• Defence Forces (Ireland)
• Irish Army
• Irish Air Corps
• Irish Naval Service
• Guard of honour
• Modern Irish Army uniform
• Steyr AUG

• The Infantry Corps | Irish Army
• Merrion Square 2015 Preparation
• 28th Inf Bn on Ceremonial Military Guard Duty - 17 August 2013
• 27 Infantry Battalion perform ceremonial drill at the National Memorial, Merrion Square