The Waterloo Fire Department responded shortly before 3 p.m. Wednesday to a call of a combine on fire in a field in the 7900 block of Gall Road.
The combine soon caught the field on fire as well.
About 15 minutes later, first responders said the combine was no longer on fire but that the fire had spread to the cornfield.
The Columbia Fire Department and Valmeyer Fire Department were both soon called to respond for mutual aid with brush trucks.
The cornfield fire was reported as being mostly out about 3:25 p.m., though there were some hot spots that could flare up that firefighters were still working on. There was also some parts of a bean field still on fire, which was being fought.
About 10 minutes later, the fire was knocked down and contained except for a few hot spots firefighters soon finished with.