Firefighters are tackling a blaze at the former Donaghy's Mill site in Drogheda, Co Louth.
The building has been vacant for a number of years and is derelict.
A number of units of Drogheda Fire Brigade are at the scene this evening trying to bring the blaze under control.
No one has been injured and it is not yet known how the fire started.
Trinity Street in the town has been closed and motorists are advised to drive with care.
The site has been the scene of several fires in recent years.
Donaghy’s Mill, beside the River Boyne, was a four-storey former mill built around 1820 and later used as a shoe factory.
It was also home to pirate radio station Boyneside Radio in the 1970s.