The
townland of Randalstown was originally known as
An Dún Mór ("the great fort"), anglicised as
Dunmore. This refers to a medieval
motte-and-bailey castle built by the Irish on the west bank of the river Main just south of the town. A castle known as Edenduffcarrick, later
Shane's Castle, was built near Randalstown in the 14th century by the
O'Neills of
Clannaboy. From at least the 1650s the town was known as "Iron Mills" (
Muilinn Iarainn in Irish, anglicised "Mullynieren"). Dunmore Park was used as a training camp for the
Ulster Volunteers during the
Irish Home Rule crisis. Randalstown has a strong history of
linen and
iron industries. A memorial to this history is in the middle of the town and made from the original turbine used to generate mains electricity for the town and items salvaged from the Old Bleach Linen Company founded by James Webb in 1864. An old linen mill chimney from the Old Bleach factory can be seen from most parts of the town. The Dorma Old Bleach factory which operated from a neighbouring site closed down in 2002. On 1 October 1989, a
Provisional Irish Republican Army (IRA) car bomb exploded outside the town's police station on New Street causing serious damage to nearby property. On 8 January 2010,
PSNI Constable Peadar Heffron was seriously injured as a bomb exploded under his car on the Milltown Road near Randalstown.
Dissident republicans were blamed for the attack. ==Demography==