The first fire destroyed three abandoned homes at 146th and Halsted streets.
Hundreds of firefighters from several neighboring suburbs helped battle the blaze.
One firefighter suffered a minor injury. Several police officers also were called to the scene.
The second fire damaged a home about a block away from the first one. Police believe the fires are related.
Chadra Gray, 37, is charged with arson after police say she was seen setting the fire.
Gray is also a suspect in the other Harvey fire, about a block away from the first fire.