Free State Army

National Army
An tArm Náisiúnta Participant in Irish Civil War
National Army Cap Badge
Active	31 January 1922 – 1 October 1924
Leaders	Michael Collins Richard Mulcahy
Area of operations	Southern Ireland, later Irish Free State
Strength	55,000
Originated as	Pro-Treaty Irish Republican Army (IRA)
Became	Defence Forces
Opponents	Anti-Treaty Irish Republican Army (IRA)

The National Army, sometimes unofficially referred to as the Free State army or the Regulars, was the army of the Irish Free State from January 1922 until October 1924. Its role in this period was defined by its service in the Irish Civil War, in defence of the institutions established by the Anglo-Irish Treaty. Michael Collins, was the army's first chief of staff from its establishment until his death in August 1922.

The army made its first public appearance on 31 January 1922, when command of Beggars Bush Barracks was handed over from the British Army. Its first troops were those volunteers of the Irish Republican Army (IRA) who supported the Anglo-Irish Treaty and the "Provisional Government of Ireland" formed thereunder. Conflict arose between the National Army and the anti-Treaty components of the IRA, which did not support the government of the Irish Free State. On 28 June 1922 the National Army commenced an artillery bombardment of anti-Treaty IRA forces who were occupying the Four Courts in Dublin, thus beginning the Irish Civil War.

The National Army was greatly expanded in size to fight the civil war against the anti-Treaty IRA, in a mostly counter-insurgency campaign that was brought to a successful conclusion in May 1923. From 1 October 1924, the Army was reorganised into a smaller, better regulated force; the term "National Army" superseded by the legal establishment of the Defence Forces as the Irish Free State's military force.