Fifteen people have been arrested in raids in Conwy and Anglesey targeting those who police suspect to supply Class A drugs in the region.
More than 250 police raided 27 properties in north Wales and north west England to tackle the supply of cocaine across the area.
North Wales Police said the strikes were its largest drugs operation in almost 20 years.
All those arrested are being held in custody in north Wales.
Police have apologised to a family after they executed a search warrant at an incorrect address.
They will be arranging for the damage to be repaired.