The village of Crinkill developed around the barracks. The 1798 Rebellion and subsequent fears of another French invasion of the west of Ireland led to fortification of the line of the River Shannon and Birr was selected as a site for a barracks because it was within a few hours march from Banagher and other fortifications on the river. Building of the barracks at Crinkill began in 1809 and was completed in 1812. The complex could accommodate over 1,200 men and 500 more under canvas and eventually included a chapel, school, its own gasworks, gym, and graveyard. The Leinster Regiment, formed in 1881, had their depot here. The barracks were handed over to the Irish Free State on 13 February 1922 and were burned down by Repubican forces on 14 July 1922. Little now survives at Crinkill except most of the perimeter wall and the graveyard.