The National Fire Prevention Association published the following article about the cause of the Great Chicago Fire:
Fire Prevention Week was established to commemorate the Great Chicago Fire, the tragic 1871 conflagration that killed more than 250 people, left 100,000 homeless, destroyed more than 17,400 structures and burned more than 2,000 acres. The fire began on October 8, but continued into and did most of its damage on October 9, 1871.
According to popular legend, the fire broke out after a cow – belonging to Mrs. Catherine O’Leary – kicked over a lamp, setting first the barn, then the whole city on fire. Chances are you’ve heard some version of this story yourself; people have been blaming the Great Chicago Fire on the cow and Mrs. O’Leary, for more than 130 years. But recent research by Chicago historian Robert Cromie has helped to debunk this version of events.