Nine people were arrested and charged with alleged drugs supply offences last Wednesday after the first raids. They appeared before Berwick magistrates the following day with eight of them remanded in custody.
A further seven - five men and two women - were arrested on Friday morning after a second wave of raids at addresses in Berwick and Ayton.
Six were charged with alleged drugs offences and four of them appeared before Berwick magistrates on Saturday. Two others were released on bail and one person was released with no further action taken.
All those charged are expected to reappear before magistrates at Berwick today (Thursday).
The arrests form part of Operation Blowtorch which got under way six months ago following community concerns about heroin in the area.
Northumberland Area Commander, Chief Supt Kevin Lambert, said: "This latest phase of the operation has gone very well, with 15 people we were targeting being arrested and charged.
"However, the operation will continue and we would urge the public to keep coming forward to us and our partners with information, to ensure Berwick retains its reputation as a low crime area."
Chief Supt Lambert added: "We want drug users to use this, and see this, as an opportunity to seek help for their drug dependency and help them move on and improve Berwick for the people who live and work here.
"The misery that drug dealing causes has a huge impact on the family of those dependent on drugs, and the neighbours who have to put up with this near to them.
"We only expect this to have had a positive impact on crime in the area. The onus is now on those dependent on drugs to do something to help themselves."
Sharon Baines, Northumberland Drug and Alcohol Action Team co-ordinator said: "We would encourage drug users to take this opportunity to seek help and support to address their problems.
"In Northumberland, the Drug and Alcohol Action Team commission a comprehensive range of treatment and support services for those people affected by drug misuse. These services provide support not only to drug users themselves, but also to the families and carers of drug users."
Anyone affected by drug misuse can contact the confidential 24 hour telephone helpline on 07702 833944.
Berwick Borough Council chief executive Jane Pannell added: "We want to tackle crime and the fear of crime and show this is an area where we don't tolerate this sort of behaviour."
The nine people who appeared at Berwick Magistrates' Court on Thursday were:
Gregg Dixon, 26, formerly of Liverpool and various addresses in the border area, but currently serving a jail term in HMP Durham.
He is charged with eight offences of supplying heroin, two of supplying cocaine, and two of possession of heroin with intent to supply.
Ian Dougal, 29, of Highcliffe, Spittal, is charged with three counts of supplying heroin, and one of possession with intent to supply.
Janine Mullins, 30, of Highcliffe, Spittal, faces four charges of supplying heroin and one of possession with intent to supply.
Martin Punton, 34, of St Andrews Road, Berwick, has been charged with two counts of supplying heroin.
James Darling, 39, of Middle Street, Spittal, is charged with two counts of supplying heroin, and one of possession of heroin.
Mathew Clazie, 39, of Middle Street, Spittal, is charged with supplying heroin.
John Betteridge, 36, of Eastcliffe, Spittal, is charged with two counts of supplying heroin, offering to supply heroin, possession with intent to supply, and possession of cannabis
John Thompson, 35, of Eastcliffe, Spittal, is charged with supplying heroin.
Alan Bloomfield, 23, of Crispin Road, Berwick, is also charged with four offences relating to the supply of class C drugs.
The four people who appeared before Berwick Magistrates' Court on Saturday were:
Mark Sleight, 26, of Sea View, Highfields, Berwick, is charged with six counts of supplying cannabis resin.
George Woodward, 30, of The Croft, Ayton, is charged with supplying heroin and cocaine.
Cath Young, 31, of West End, Tweedmouth, faces two charges of possession of diazepam and supplying heroin.
Ian Chowles, 29, of West End, Tweedmouth, is charged with possession of a quantity of cannabis resin, possession of diazepam and possession of methadone.