More than 50 officers took part in the operation, which also recovered Class A drugs, cash and a suspected stolen vehicle.
The early morning warrants followed several months of preparation using intelligence gathered across the district, including Heywood, Middleton and Newhey.
Neighbourhood officers worked alongside organised crime and county lines teams to tackle suspected organised crime groups.
A 33-year-old man and a 33-year-old woman were arrested on suspicion of cultivating cannabis and abstracting electricity. A 61-year-old man and a 61-year-old woman were arrested on suspicion of the same offences.
Police also arrested a 35-year-old man on suspicion of possession with intent to supply Class A drugs and a 28-year-old man on suspicion of possession with intent to supply Class B drugs.
A 78-year-old man was arrested on suspicion of handling stolen property.
All seven remained in custody for questioning at the time of the police update. Enquiries are ongoing.
GMP said the three cannabis farms contained substantial numbers of plants, growing equipment and sophisticated set-ups. Officers also recovered significant quantities of cash, Class A drugs and a suspected stolen vehicle.
Images released by police showed officers executing a warrant at a farm off Huddersfield Road in Rochdale.
Police said the operation responded to issues in Heywood, Middleton and other parts of the district. Investigations will continue over the coming weeks as officers seek to secure charges where appropriate.
Inspector Graham Cooke, from GMP’s Heywood and Middleton team, said, “This day has been a long-time coming, and has seen a huge amount of work put into its preparation and execution.
“Dozens of officers have assisted in the work today, putting a firm stamp on OCGs who terrorise and disrupt communities across our areas. This is the exact sort of work that we know people want to see I am glad we have secured multiple arrests and drug seizures.
“We will now look to start putting together files for the CPS where possible, while continuing our work to tackle crime wherever we find it.”
