The 1860s was a period in which physical-force nationalists were once again secretly organising and it was later claimed by the Fenian leader John Devoy that the IRB had recruited Irishmen to the Fenians from within the ranks of the 61st, as well as other British regiments. Devoy later recalled that
‘One of the most intelligent and best educated of the Fenian soldiers was Corporal Thomas Chambers, who was Centre of the 61st. It was supposed to be an English Regiment but there were not one hundred men in it who were not Irish, and there were 600 Fenians. It was the banner Fenian regiment.’
In 1866, while the 61st was in Ireland, Devoy and others devised a plan to seize Dublin by force. Part of the scheme was for the Fenians to capture Richmond Barracks with the help of the Irish soldiers serving there with the 61st. The plan was abandoned but the IRB went on to launch a rebellion the following year, which ended in failure.