Firefighters are tackling a huge blaze at Newsome Mill.
Crews from Huddersfield Fire Station were called to the scene at around 4am, joined by 20 fire engines from fire stations across West Yorkshire.
Ruth Street in Newsome was closed in both directions and homes nearby were evacuated at around 5am.
The floor and the roof of the listed building have collapsed.
Eyewitness James Hollingworth, of Brackenhall, was DJing at Camel Club in Huddersfield town centre and went to Newsome after seeing reports of the fire on Facebook.
He said: “It was very dramatic. There were loads of firefighters there trying to bring it under control.
“Spark were flying everywhere. I saw all the floors collapsing.”
James added he could see the fire from the top of Chapel Hill on the ring road when he was leaving work in the small hours.
Firefighters are now looking at the safety of the unoccupied mill, which is known for its clock tower.
