The Great Chicago Fire of 1871 Remains Shrouded in Mystery


There are some great myths in American history, but ask anyone in Chicago and they’ll tell you that they don’t come any bigger than that of Mrs O’Leary’s cow and the Great Chicago Fire. It has gone down in local lore, alive in the history of Chicago for so long that people have ceased to care whether or not the legend has any basis in fact. The story itself is simple – that the fire was started by a cow that knocked over an oil lamp or a lantern, thus starting the fire – but the context, the consequences and the circumstances of the conflagration have added layers of intrigue to the tale in the near 150 years that have passed since that seminal moment in the history of the United States.

Like any great investigation, we should start with the scene of the crime. The fire certainly did start at the O’Leary residence, a small wooden house on DeKoven Street, now estimated to be at the corner of Roosevelt Road and Canal Street in the Near West Side, just over the canal and the train tracks from the Loop.

The fire initially took hold in the barn that housed the O’Leary family’s animals – which held plenty of fuel for the flames in hay, straw and the timber framing of the structure – and was easily blamed on the livestock. Reports also suggest that an illicit gambling den may have been housed in the barn, with one of the patrons the culprit, but as befitting such a huge fire, all the evidence went up in smoke.

Mrs O’Leary’s Cow.

Whatever it was that started the fire, the spread of it was rapid. Within minutes the whole surrounding area was aflame, the inferno fuelled by wooden houses, topped with roofs made from shingle and tar that transported the fire from dwelling to dwelling in the densely-populated Near West Side. The fire took place in October, at the end of a bone dry summer in which Chicago had barely seen a drop of rain: the whole city was a tinder box waiting to go up.

Indeed, the drought that afflicted Chicago would have terrible consequences on the whole Midwest, as nearby communities also suffered conflagrations of their own. Peshtigo, a logging town just over the state line in Wisconsin, endured the deadliest fire in US history on the same day as the Great Chicago Fire while across Lake Michigan, the towns of Manistee and Holland were also reduced to cinders.

The atmospheric conditions caused the fire to spread swiftly. A breeze blew the flames northeast, directly towards the Downtown area. The confusion lead to the fire department, well-trained and practised in fighting barn fires, to the wrong address. By the time they arrived at O’Leary’s, the flames were beyond their control. They hoped that the Chicago River would form an unbreachable barrier, but the excess of loose wood that was held in the lumber yards along the river’s edge gave so much fuel that the flames spanned the water and caught on the other side, abetted by an ever-strengthening wind.

With the fire taking hold in the heart of Chicago, the panic was total. The mayor ordered all the prisoners in the courthouse to be released for their own safety when the building caught fire and when it eventually collapsed, the sound of the bell in the bell tower falling was heard for miles around.


The meteorological conditions that characterize major fires began to take hold. With enough wind and enough fuel, fires create their own ecosystems as hot air is forced up and dislodges colder air, causing a fire whirl. This threw flaming debris in every angle, spreading the fire further through the city and over the river for a second time. The waterworks caught on fire and collapsed, removing the one store of water that may have been able to save Chicago.

The fire would range all the way through the 8th and into the 9th, stopping only in the evening when rain mercifully fell. When the city cooled sufficiently for investigators to enter – a process that took several days – the damage could be surveyed. A 4 mile long, ¾ mile wide swath had been cut through the centre of the city, destroying everything in its wake. Over 100 people lay dead and another 100,000 were homeless, while a full third of the business capacity of Chicago had gone up in smoke.

The reconstruction was swift. Donations were sent from all over America to aid in the housing of the homeless and a rebuilding of the city, while firefighters from Milwaukee and all over Illinois arrived to help douse the flames. Almost as swift were the rumours that began to circulate about the source of the fire, with Mrs. O’Leary and her livestock at the centre of them. The Chicago Tribune mentioned the cow in their first edition to be published after the fire and it was all over the city before the flames had even cooled. The O’Learys could not have been a more perfect target for the prevailing political mores of the time.