Officers were on the scene just east of Stony Island near 107th Street early Wednesday for what they were calling a joint helicopter operation.
Authorities say the open field contains more than 1,000 cannibis plants, some said to be as tall as Christmas trees. Police also said it might be one of the largest discoveries in Chicago's history.
Chicago police said they remove the cannabis plants Wednesday, most likely by burning them, they said. Authorities also said they would hold a news conference later Wednesday morning.