Six men have been jailed after nearly 4kg (9lbs) of drugs were seized during a police operation.
The three-year investigation, known as Operation Decode, was led by Avon and Somerset Police, with Wiltshire Police and Devon and Cornwall Police.
During the operation some £60,000 in cash and significant quantities of drugs were found and seized.
The men pleaded guilty and were sentenced at Bristol Crown Court on Thursday.
A seventh man was given an 18-month conditional discharge.
Operation Decode was a "major investigation" into the supply of controlled drugs in the South West, Avon and Somerset Police said.
It culminated in a day of action on 16 March 2021 in which warrants were executed across the region, leading to seven suspects being charged with various offences relating to drug possession and supply.
Drugs seized by police included:
Det Ch Insp Simon Dewfall, of the Avon and Somerset complex crime unit, said: "We are committed to tackling the organised supply of illegal drugs and protecting the most vulnerable people in our communities from harm.
"The combined value of cash and drugs officers recovered as part of Operation Decode provides some insight into the scale of organised crime we've been able to disrupt."
Sebastian Dymond, 38, of Ashton, Bristol, was the principle figure in the organised crime group, responsible for distributing multiple kilos of cocaine and cannabis across the region, police said.
He was charged with six offences relating to possession and supply of class A, B and C drugs and sentenced to 12 years imprisonment.
The investigation found that Dymond had a number of customers across the region.
This included Grant McEvansoneya, 31, of Barnstaple, who had purchased significant quantities of cocaine and cannabis for onward sale in the North Devon area.
He was jailed for eight years after being charged with three counts of conspiracy to supply class A and B drugs.
Daniel Parsons, 39, of Hartcliffe was charged with conspiring to supply class A drugs after investigators found evidence that he had also supplied cocaine to McEvansoneya.
He received a two-year prison sentence, suspended for 18 months, plus unpaid work totalling 150 hours.
The investigation also found that Dymond had purchased large amounts of prescription medication and steroids from Kalvir Singh, 42, of Chippenham, for onward sale to customers.
Singh was sentenced to two years imprisonment, suspended for 18 months, for three charges relating to possession and supply of class B and C drugs and two counts of possession of criminal property.
He was additionally ordered to complete 200 hours of unpaid work.
Also working closely with Dymond was Maksymillian Zurek, 33, of Lawrence Weston, who was jailed for six years and six months after pleading guilty to four charges which included possession of and conspiracy to supply class A and B Drugs, and possessing a prohibited weapon.
Oliver Duxbury, 35, of Trowbridge, was found to have purchased cocaine from Zurek on multiple occasions and was sentenced to 30 weeks imprisonment suspended for 18 months, plus 150 hours unpaid work.
A seventh man was given an 18-month conditional discharge after pleading guilty to possession with intention to supply cannabis.
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