The Peshtigo Fire began October 8, 1871, near Green Bay, Wisconsin. The firestorm consumed 1.2 million acres of timber, destroyed 12 communities, and resulted in the most deaths by fire in the U.S. history - estimated deaths numbered 1,500 people and possibly as many as 2,500. But the same day the Great Chicago Fire began, destroying 3.3 square miles of the city's central business district, while the Great Michigan Fire destroyed the cities of Holland, Manistee, Port Huron and White Rock (in addition to 2.5 million acres of Michigan forest).

More Info: en.wikipedia.org