Drug busts have targeted huge gangs leaders who operate on county lines as 18 people have been arrested in a series of raids.
Northamptonshire Police carried out three days of intelligence-led action in Kettering, and in London with the support of The Metropolitan Police.
The force said it was one of the biggest operations it had run, as more than 250 officers took part in Operation Serpent, and had been "months in the planning".
Two men, aged 28 and 29 and one woman, aged 53, as well as 15 people in Kettering were arrested on suspicion of conspiracy to supply Class A drugs, human trafficking and modern slavery offences.
Around £5,000 in cash as well as Class A and B drugs, knives and a corrosive substance were also seized as part of subsequent searches of the addresses.
Detective Inspector Steve Watkins, who led the operation, said they wanted to "loud and clear message to all those who would come to our county and try to cause us harm".
The police also used modern slavery laws for the first time to target those behind the "exploitation of vulnerable children".
Mr Watkins said the dealers were targeting and recruiting "young people to supply drugs on their behalf while holding them in servitude."
County lines drug dealing involves organised crime groups from larger cities setting up in smaller towns such as Kettering with local dealers.
Mr Watkins added the gangs "have spread misery and caused significant harm to innumerable people."
Assistant Chief Constable Simon Blatchly, head of operations at Northamptonshire Police, said the force's activity tackles and significantly disrupts organised crime and "crucially, safeguard vulnerable young people who fall prey to those peddling drugs."
"County Lines criminality remain a threat, but Operation Serpent sends out a very clear message to those involved in drugs supply that Northamptonshire Police: We will pursue you tirelessly and relentlessly."
Anyone with information about suspected drug dealing in their communities should contact Northamptonshire Police on 101 or call Crimestoppers on 0800 555 111.