Crews responded around 6:30 p.m. Sunday to Bean's Lumber Company, located on the 1000 block of 2nd Avenue.
Officials say tanker engines from surrounding communities were called in to help fight the fire.
The fire was brought under control shortly before 10 p.m.
A nearby barn was full of horses, officials say, all of which escaped unharmed.
No injuries were reported.
Officials say the building that caught fire is a complete loss.
No word on what caused the blaze.
The mill uses lumber to make furniture.