Stoystown Fire Chief Dave Johnson said the current owners use the cabin along U.S. Route 30 as a hunting cabin.
But the chief said the building dates to at least 1745, though he said records pertaining to the building have been destroyed.
The chief said the building was not insured. He's called in a state police fire marshal to investigate, but does not believe the fire is suspicious.
The fire was reported about 10:50 a.m. Sunday.
Stoystown is about 50 miles southeast of Pittsburgh.