More than £140,000 worth of drugs and £11,000 in cash, was seized during a police operation this week across Huddersfield.
Police made 21 arrests after raiding 18 addresses including Crosland Moor, Marsh, Lindley, Almondbury, Paddock, Milnsbridge and Birkby.
Officers in Kirklees have been gathering information about drug production and supply in the district since June.
They had back up from armed police, the dog section and officers from all districts across West Yorkshire during the three-day operation.
17 people were arrested for offences of conspiracy to produce and supply Class B drugs, possession with intent to supply Class A drugs and public order offences.
All have been released pending further investigation.
A further four people, who were arrested before the three-day operation, have also been released pending further enquiries.
The haul included £134,000 of Class A drugs and £7,000 of Class B drugs and around £11,000 in cash.
Detective Chief Inspector Tony Nicholson of Kirklees CID, said: “Overall a total of 21 people have been arrested for various offences including a number of drugs offences and in connection with recent firearms incidents in the District.
"My message to everybody in Kirklees is that we will not tolerate firearms and drugs on our streets and, to those who are involved in this type of criminality, we will come for you.
"This was an intelligence led operation and it is important that we work with our communities and partners to identify, arrest and convict anyone who is involved in any kind of crime that involves drugs or firearms."