Iron County was created in 1893 mostly from the eastern part of Ashland County, but also from some land which had been part of Oneida County; Vilas County was created from Oneida County at the same time. The name of the new county came from the iron ore deposits which had been discovered in the area. Iron mining was very important to the local economy, and when the iron mines began to close in the 1950s and 1960s, it was devastating to this part of Wisconsin and Upper Michigan.
The county seat is Hurley, which is just across the Montreal River (which is the state border) from Ironwood Michigan.
The current Iron County courthouse is located at 300 Taconite Street in Hurley. The original county courthouse is located at 303 Iron Street in Hurley. The old courthouse was built in 1893 as the town hall for the former Town of Vaughn, it was sold the following year and became the Iron County courthouse. It now serves as the Iron County Historical Museum.