The haul weighs 8 tons and has an estimated street value of over $40 million. It was seized Tuesday near a warehouse in the Chicago area.
Investigators had received information that a shipment likely originating in Mexico was headed to the area. The pot was apparently going to be divided and distributed through local drug suppliers and street gangs.
"When we make large seizures like this where we can affect the street level sale of narcotics, no matter which it is, it impacts on the crime in the city," said Chicago Police Superintendent Garry McCarthy.
Police have not made any arrests. They say the investigation is ongoing.