Barley House in North Warren was built for the Wetmores in the 1830s.
Firefighters from nine departments were on the scene for several hours, with some not leaving until this morning to check for hot spots.
A state police fire marshal was on the scene, but has not released any information yet on the cause of the blaze.
The building was used as a nursing home from the early 1960s until 2011. Barley House was listed in a Warren County Sheriff’s sale on July 31.