Officers from Dumfries and Galloway Road Policing Unit made the discovery during routine patrols after stopping an Audi A6 travelling northbound at about 5.10 pm on Wednesday.
On speaking with the driver, officers detected a smell of what they believed was cannabis. Following a search of the car, officers discovered a quantity of herbal cannabis, worth an estimated street value of £105,000.
A 30-year-old man was arrested and charged in connection with the seizure and is due to appear at Dumfries Sheriff Court this week.