Search warrants were carried out with heroin, cocaine and illegally obtained tablets among the substances seized in a number of locations as part of Operation Ram in January and February.
The locations include Shetland, Orkney, Caithness, Wester Ross, Easter Ross, Inverness, Badenoch, Nairn and Lochaber.
A large-scale cannabis cultivation was also uncovered.
Police said eight people have or will be reported in connection with the supply of controlled drugs - and the figure is expected to rise with ongoing enquiries.
Detective Inspector Peter Mackenzie said: “We are committed to disrupting the activities of those involved in serious crime at all levels and Operation Ram is an established means of doing that.
“This operation brought together officers from a number of departments including local policing officers, officers from the Community Investigation Unit, as well as colleagues from the Specialist Crime Division and the Operational Support Division.
“Time and again the public tell us that they are sick of the way that drugs are destroying young people, families and neighbourhoods.
“This is a message that we are listening and responding to these concerns, and we are taking action against the criminals who cause this damage.
“While we are encouraged by these recent seizures, we will never become complacent and will continue to work every day to tackle the drug trade and the problems it brings and causes.
“We want to ensure that the Highlands and Islands are a hostile environment for drug dealers.”
Approximately £17,000 in cash was also seized by officers.
Mr Mackenzie added: “Much of the recent Operation Ram activity is a direct result of intelligence shared by members of the public who do not tolerate drugs in their community.
“I would take the opportunity to thank the public for their continued support and offer the assurance that every piece of information we receive is fully assessed and thereafter acted upon where appropriate.
“This community intelligence is used to shape our operational activity - if you let us know of your concerns then we will do the rest.”