A raid on a house discovered drugs with an estimated street value of £1.5 million.
Officers executed a search warrant at a house in Harcourt Stereet, Raunds, on July 24 and found almost 200 cannabis plants in the loft.
During the search, boxes of packaged herbal cannabis were seized along with a significant amount of heroin.
Two people - a 30-year-old man and a 32-year-old woman, both from Raunds - were arrested at the address and have been charged for offences related to possession of controlled substances with intent to supply.
Sector Commander, Inspector Vaughan Clarke, said: “I have a proactive team of officers who undertake a lot of research and intelligence gathering in relation to local criminals.
"As part of a local policing operation, we developed an interest in this address and garnered intelligence suggesting that drug dealing was taking place and acted swiftly on that intelligence.
"This is one of the most significant seizures of drugs in this area in recent years and is our second significant drug seizure in a matter of weeks.
"We are determined to continue targeting those criminals who are prepared to supply drugs in our communities and anyone involved in this type of crime should be worried that they are next on our list.
"We have seen significant reductions in crime in recent years and already this year we are seeing the lowest levels of crime recorded in modern times.
"We can only have this sort of success with the assistance of the public and I would urge anyone with information relating to drug related crime to call Northamptonshire police or Crimestoppers.”