Mrs. O'Leary and her cow have been the most common answer to the question, “Who started the Great Chicago Fire?” However, this legend has very little fact behind it. The idea that Mrs. O'Leary and her cow were to blame started in the October 9, 1871, evening edition of the Chicago Evening Journal. This paper reported that a cow kicked over a kerosene lantern while being milked by a woman. Since the fire originated in the O'Leary barn, people started blaming Catherine O'Leary for causing the tragic blaze. The truth is that Mrs. O'Leary was not even in her barn when the fire started. She was actually in bed with her husband Patrick and their children, and to this she and her husband testified during the city investigation.
Along with their testimonies, several other factors make it unlikely that Catherine O'Leary started the fire. First of all, the barn and its contents were not insured. The O'Leary family ran a milk business, and in their barn were five cows, a calf, a horse, several tons of hay, and nearby two tons of coal. Everything the family needed for the winter was contained in the barn. Therefore, if Mrs. O'Leary had started the fire, she would have quickly tried to put it out or run for help. Instead the O'Leary family had to be alerted about the fire in order to get out of their home.
The question then arises as to who actually set the fire. Two men remain suspicious to this day: Daniel “Peg Leg” Sullivan and Dennis Regan. Both men were the first to arrive at the scene of the fire. Both men tried to save the O'Leary's property, and both men had several inconsistencies in their testimonies. It is possible that the men were in the barn and accidentally started the fire from a dropped pipe, match, or lantern. However, it can not be known for sure who started the fire that burned almost four square miles of Chicago. It can be safely assumed though, that Mrs. O'Leary and her cow did not start the fire, and should not go down in history as causing one of the worst disasters in the city of Chicago.