A fire at historic John H. Stevens House in the early hours of Saturday morning is the third blaze at the museum since Aug. 30.
Minneapolis Fire Department says the fire was reported at the museum in Minnehaha Park at 3:42 a.m., with the building currently boarded up and under construction from two past fires, both of which are under investigation.
In the latest blaze, crews found "heavy fire" coming from the rear corner of the building, and found fire on the first and second floor of the exterior, extended through the roof near the chimney.
Nobody was found inside the building, with crews able to extinguish the fire albeit with "extensive overhaul," which typically means opening up walls, ceilings and voids to ensure the last vestiges of fire were out.
The building has been re-boarded up, with the cause of the fire under investigation.
It comes after a fire caused significant damage at the museum – though most of its contents were saved – on Aug. 30, with another fire reported on Sept. 20.
According to Minneapolis Parks and Recreation, the house was built in 1849-1850 near St. Anthony Falls, with John H. Stevens becoming the first authorized resident on the west bank of the Mississippi River in what would later be known as Minneapolis.
The house was eventually moved in 1896 to Minnehaha Park, which was chosen over other suggestions of Loring Park and Riverdale Park. The house was moved with the aid of 10,000 schoolchildren who pulled ropes to shift it.