The raid took place at an address in Copgrove, Harrogate on Tuesday 18 September 2012 when officers seized in excess of 500 plants.
As well as seizing the plants, police have also confiscated hydroponic equipment used to cultivate the cannabis.
The investigation to identify and arrest those responsible remains ongoing.
Detective Sergeant Jason Marchant, of Harrogate CID, said:
This was clearly a sophisticated operation run by professional criminals.
This seizure has removed a significant amount of drugs from the supply chain.
I want the raid to send a clear message to anyone involved with the production and supply of illegal drugs that their activities will not be tolerated. North Yorkshire Police will act quickly when we receive intelligence to disrupt criminal behaviour at every level.
If you can help to identify those responsible for this operation please contact the police or Crimestoppers straight away.
Anyone who can help the police with their enquiries is asked to contact on 101, press option 2 and ask for Harrogate CID. Alternatively information can be emailed to firstname.lastname@example.org.
Or call Crimestoppers anonymously on 0800 555 111 quoting reference number 12120156630.