The Volunteers (also known as the Irish Volunteers) were local militias raised by local initiative in Ireland in 1778. Their original purpose was to guard against invasion and to preserve law and order at a time when British soldiers were withdrawn from Ireland to fight abroad during the American Revolutionary War and the government failed to organise its own militia. Taking advantage of Britain's preoccupation with its rebelling American colonies, the Volunteers were able to pressure Westminster into conceding legislative independence to the Dublin parliament. Members of the Belfast 1st Volunteer Company laid the foundations for the establishment of the United Irishmen organisation. The majority of Volunteer members however were inclined towards the yeomanry, which fought and helped defeat the United Irishmen in the Irish rebellion of 1798.
As far back as 1715 and 1745, self-constituted bodies of defensive local forces where formed in anticipation of Stuart invasions. For example, in 1744 with the declaration of war with France and in 1745 the landing of Prince Charles Edward in Scotland, a corps of 100 men was enrolled in Cork, known as the "The True Blues", which formed one of the regiments of the "United Independent Volunteers".
In 1757 and 1760 there were volunteer units formed due to the Seven Years' War and due to the French landing at Carrickfergus in 1760. The roll-call of the militia that marched on the French at Swinford listed in the "Collectanea politica", published in 1803, was titled "Ulster volunteers in 1760". From 1766 onwards units were embodied by local landlords in various parts of the country for the preservation of peace and the protection of property. Early volunteer groups (which later became part of the Volunteers) included: First Volunteers of Ireland (1 July 1766); Kilkenny Rangers (2 June 1770); First Magherafelt Volunteers (June 1773); and the Offerlane Blues (10 October 1773).
The rise of the Volunteers was a spontaneous event fired by patriotism and the threat of invasion, as another French landing was anticipated when war broke out in 1778. With British troops being dispatched from Ireland for the war with the American colonies, the landed gentry reacted nervously, and misunderstandings arose about Ireland's defence capabilities. Claims that Ireland was ill-prepared for an attack, along with alleged negligence from Dublin Castle, was used to justify the existence of Volunteer companies and their role in defending Ireland. In fact around 4,000 soldiers had been dispatched to the American colonies, leaving as many as 9,000 behind in Ireland.