The national flag of Ireland is a vertical tricolour of green, white, and orange, and it’s proper proportions are 1:2 (the width is twice the height). It has no formal meaning in the Irish Constitution however is generally perceived as the green representing Catholicism, the orange Protestantism, and the white an enduring truce between the two.
It was presented as a gift to Thomas Francis Meagher in 1848 by a group of French women sympathetic to the Irish cause, however it was not until the 1916 Easter Rising when it was raised above the GPO in Dublin that it came to be regarded as the national flag.
It was adopted in 1919 by the Irish Republic during the war of independence, and subsequently by the Irish Free State (1922–1937), and gained official status under the 1937 Constitution of Ireland.
The Department of the Taoiseach takes responsibility for the flag in an advisory role and specifies the guidelines for it’s use. They also specify the exact colours of the green and the orange.
The Irish Flag as it should be (feel free to copy and use)…
For reference the hex codes for the colours are:
Green – #009B48 (Pantone: 347)
White – #FFFFFF
Orange – #FF7900 (Pantone: 151)
The Irish harp first appeared on a green flag in 1642 when Eoghan Rua O’Neill, leading the armies of Ulster, was waging a rebellion against English rule. The Society of United Irishmen proclaimed the harp as Ireland’s national symbol through its use in the Irish Rebellion of 1798, and with the passage of time the green flag and the golden harp became a symbol of the Irish nation.