4th (County Fermanagh) Battalion, Ulster Defence Regiment (4 UDR) was formed in 1970 as part of the 7 original battalions specified in The Ulster Defence Regiment Act 1969, which received Royal Assent on 18 December 1969 and was brought into force on 1 January 1970. It was amalgamated with the 6th Battalion, Ulster Defence Regiment in 1992 to form the 4th/6th Battalion, Ulster Defence Regiment.
6th Battalion was a part of the 7 original battalions specified in The Ulster Defence Regiment Act 1969