Hundreds of cannabis plants were seized by police during a series of coordinated drug raids.
Officers carried out intelligence-led warrants on Thursday and Friday at 12 addresses in Mansfield Sutton-in-Ashfield, Skegby, South Normanton and Ilkeston.
Drugs worth more than £500,000 were found at two properties in Beech Avenue, Mansfield on Thursday.
The seized drugs and associated equipment have been taken away and will be destroyed.
Extensive remedial work will also be required to fix dangerously bypassed electrics.
Three men, aged 57, 26 and 21 were arrested on suspicion of drug offences and later released on bail.
The action follows a series of similar coordinated raids carried out in Ashfield in November.
Inspector Jon Hewitt, of Nottinghamshire Police, said: “Cannabis cultivation is a very serious offence and is often linked to violent organised crime groups from home and abroad.
“It is also very often linked to other very serious offences such as human trafficking and modern slavery.
“Neighbouring residents, meanwhile, are also placed at considerable risk of fire from these pop-up drugs factories.
“So if you have reason to suspect a property in your street please contact the police and tell us about it. We will listen, we will investigate and we will look to take this kind of firm action.”