Farm buildings at Stokesley have been damaged in an incident which is being investigated.
Police in the Hambleton area are treating the blaze as suspected arson.
Station Manager Tony Walker of North Yorkshire Fire and Rescue said: “My colleague and I are currently investigating the cause of this fire near Stokesley.
“The fire has caused substantial damage. Well done to the crews that prevented the fire spreading to adjacent property.”
Anyone who has information that could help the investigation is urged to call 101, opt. 1, quoting reference 12230065117 or Crimestoppers anonymously on 0800 555 111.
It happened at Tanton Grange Track, Stokesley
Crews from Stokesley, Northallerton, Danby, Coulby Newham, Thornaby and Middlesborough responded to three connected barns on fire.
The barns measured approx 40m x 24m and contained approx 2000 straw bales.
Crews used 4 breathing apparatus, 2 hose reel jets, trash pumps and suction hoses.