Sheriff Tom Dart says it has a street value of 20 million dollars.
A wall of marijuana was on display at a police evidence warehouse Friday morning.
Sheriff's police were acting on a tip from an informant when they made the discovery in a home in west suburban Lyons.
The Sheriff's Department provided these pictures of the pot stacked up inside the house.
Dart calls it one of the largest busts in the department's history.
Frederico Moreno, 35, was arrested and charged with manufacturing and delivery of cannabis.
Moreno is expected to be in bond court Saturday.