The McLean County Courthouse was built between 1900 and 1903 after the Great Fire of June 1900. In the 1960s the courthouse was not large enough to support all the court, government offices and employees that were based there. A debate began as to whether the courthouse should be razed and replaced with a new building, or whether the building should be preserved. The courthouse was finally replaced in the 1970s by the McLean County Law and Justice Center. The McLean County Historical Society entered into an agreement with the County to be a tenant of the Courthouse building in 1991.

The collection includes documents regarding the transition of the McLean County Courthouse from its role as the County Courthouse to its role as the home of the McLean County Historical Society and McLean County Museum of History.