The rings allegedly operated in or near south suburban Robbins and Harvey, but customers came from a wide area.
All 16 suspects are charged with drug offenses.
Officers are hunting for 24-year-old Resean Ridgner, of Markham, 21-year-old Marcus Gillespie, of Dolton; and 20-year-old Desmond Scott, of Robbins.
"Nearly 500 packets of heroin and over $200,000 in suspected drug proceeds have been recovered, and that may just be the tip of the iceberg," said Mike Kosanovich, assistant special FBI agent in charge. "In a recent report, Chicago was considered to have one of the worst-- if not the worst-- heroin problems in the country."
"I don't think anybody should be deluded that this brings anything to an end. There's more than needs to be done, but this is a model of how we collectively need to work," said Cook County Sheriff Tom Dart.
The task force of law officers was helped by tips and telephone wiretaps.
