A one-alarm fire Saturday morning destroyed a barn on Green Valley Road near Union Bridge.

Firefighters from Union Bridge, New Windsor, Westminster, and Libertytown and New Midway in Frederick County responded to the fire at 9: 04 a.m. after a passer-by called it in.

The fire was under control in 20 minutes, though firefighters remained at the scene for three hours.

Damage to the 20-foot by 20-foot barn was estimated at $10,000.

The animals in the barn were not injured.

The state fire marshal's office is investigating the cause.