The fire was confined to a common area near the entrance to the mansion, according to the Winona Police Department.
The fire, which required off-duty firefighters to be called for assistance, resulted in minor fire, smoke and water damage to the building.
The fire did not result in any injuries, but the department reported one resident had to be assisted in evacuating the building by firefighters.
The residents of the mansion are being assisted by the Red Cross to find new housing.
The cause of the fire remains under investigation.
The mansion was sold earlier this year to the Kappa Chi Fraternity for $1.85 million, over double the estimated market value of the mansion, according to Winona County’s commercial sale records.
Kappa Chi chapter president Creighton Butler said that the fraternity has not moved into the mansion yet and the residents had leases from before the purchase of the property.
He said the sprinkler system activated and helped contain the fire to the common space. The building’s fire alarm system automatically reported the blaze to the Winona Fire Department.
Butler said there was “a lot to be figured out still” for the fraternity regarding its plans to move into the mansion.
The mansion, built in 1857 by one of Winona’s founders, Henry Huff, has been on the National Register of Historic Places since 1976.