Avon and Somerset Police has revealed it took action to disrupt illegal drugs networks more than 1,200 times across the region last year.
They included seven arrests and 98 interventions as part of the regional Operation Scorpion to tackle the issue in November.
The networks are run by organised crime gangs and often exploit young people and children as couriers.
The phrase 'county lines' refers to the mobile phone numbers used to take orders, often by dealers away from the location but who can then organise local deliveries.
The networks reach right across the region from distant cities into local communities.
A force spokesperson said: "County lines refers to illegal drugs being moved across the country, often out of larger cities to smaller towns and villages.
"Organised criminal groups exploit vulnerable people and children to transport the drugs The ‘county line’ is the mobile phone line used to take drug orders.
"It doesn’t happen here though, right?
"Sadly, wrong. Last year, we recorded 1,267 drugs-related disruptions to organised crime groups and county lines, as we worked to protect our communities from drug dealing and its associated violence, exploitation, and abuse.
"These included seven arrests and 98 disruptions made during our latest regional Operation Scorpion work in November,
"Our work to disrupt and dismantle county lines continues. If you have any information or suspicions about drug dealing activities or associated crime, please tell us. Call 101 (always 999 in an emergency) or report online.
"Or you can speak anonymously to Crimestoppers on 0800 555 111."