Heather Weeden was ordered to be held on $850,000 bail.
The fire, which was set on Jan. 7, caused $4.5 million dollars in damages. Police were also seeking two men who were spotted shoplifting on Walmart surveillance cameras after the fire was set.
The Walmart has been closed for three weeks.
The Chicago Tribune reports that Weeden is also suspected of a similar arson at a Meijer store in Northwest Indiana.