Daniel "Pegleg" Sullivan was a Chicagoan who is often credited with being the first to sound the alarm when a fire broke out in Catherine O'Leary's barn on October 8, 1871, the beginning of the Great Chicago Fire. More recent evidence is that Sullivan was responsible for the fire.

In his testimony before the Fire Department inquiry on November 25, 1871, Sullivan claimed he saw the fire coming through the side of the barn and ran across the street to free the animals from the barn, which included a cow owned by Sullivan's mother.

A study of the layout of DeKoven Street, where the fire began, indicates that Sullivan would not have had a clear view of the fire from where he claimed to have been standing.

Sullivan also made a confession shortly before his death in which he stated that he had been in the barn on the evening of October 8 and had been smoking a pipe. He believed that ashes from the pipe started the fire.

In October 1997, the Chicago City Council recommended that Sullivan be recorded as the person who started the fire.