The Great Chicago Fire of 1871--National Geographic Kids Magazine
The story of a young girl's escape from the blaze. Also from this site links to NFPA and the basic info on the Chicago fire:
Chicago in 1871 was already a big city, bustling with more than 334,000 residents. Its streets, sidewalks, and most of its buildings were made of wood. Hay and straw were inside every barn. To make the situation worse, people used candles and oil lamps.
Fires had been common that year because of the dry weather. The Chicago Fire Department was overworked and underequipped. On Saturday, October 7, firefighters began putting out a fire that wiped out four city blocks. It took them 16 hours. By Sunday evening the men were exhausted. Then around 8:45 p.m., a fire began in the barn of Patrick and Catherine O’Leary.
FROM THE BEGINNING, EVERYTHING WENT WRONG
Human error then made a bad situation worse. One firefighter later said, “From the beginning of that fatal fire, everything went wrong!” A watchman atop the courthouse saw smoke rising from the O’Leary barn, but he assumed it was coming from the previous fire. When he finally realized a new fire was blazing, he misjudged its location. His assistant sent a message to the fire stations, but he mistakenly directed horse-drawn fire wagons to a location about a mile from the burning barn. When the fire department finally reached the barn, its equipment was no match for the blaze. The new fire raged on.
More links:
Web of Memory http://www.chicagohistory.org/fire/
Did the Cow do it? http://www.thechicagofire.com/
Chicago Public Library http://www.chipublib.org/004chicago/disasters/great_fire.html