The Peshtigo fire was a large forest fire on October 8, 1871, in northeastern Wisconsin, United States, including much of the southern half of the Door Peninsula and adjacent parts of the Upper Peninsula of Michigan. The largest community in the affected area was Peshtigo, Wisconsin, which had a population of approximately 1,700 residents. The fire burned about 1.2 million acres (490,000 ha) and is the deadliest wildfire in recorded history, with the number of deaths estimated between 1,500 and 2,500. The exact number of deaths is debated. Data from mass graves, both those already exhumed and those still being discovered, show that the death toll of the blaze was most likely greater than the 1889 Johnstown flood death toll of 2,200 people or more.
Occurring on the same day as the more famous Great Chicago Fire, the Peshtigo fire has been largely forgotten, even though it killed at least five times as many people.