The force today announced that it was teaming up with other agencies for a week of action designed to disrupt the criminals involved.
It will include marked patrols developing intelligence about county lines activity and co-ordinated action in each district.
Detective Chief Inspector Carl Galvin, director of intelligence for West Yorkshire Police, said: "County lines crime is something we take very seriously. It is a relatively new term to describe drug dealing activity whereby drugs are supplied across cities and counties often using vulnerable and exploited victims.
“It is a crime that can directly impact on the communities we serve and in particular vulnerable and exploited victims who are being forced or coerced into doing the ‘dirty work’ of others.
“This is not something that we will tolerate - we know about it and have been taking action to tackle it. Much of this action is ‘behind the scenes’ so not immediately visible to members of the public or the criminals we are targeting."
County lines networks use dedicated mobile phone lines to expand existing drug dealing operations into new markets, particularly smaller towns and rural or coastal areas.
The criminals will often use and exploit young children and vulnerable adults to commit the crime and will use violence and weapons to get what they want.
It cuts across many different types of crime including child sexual exploitation, drug dealing, violence, gangs, modern slavery and missing people.
Det Chief Insp Galvin said: "The main purpose of this week of action is to reassure the communities we serve that action is being taken and at the same time safeguard and protect those who are exploited by those involved in these crimes and to let the criminals who choose to get themselves involved in county lines crime know that we will robustly enforce the law and bring them to justice.
“I am also appealing directly to members of the public to know how to spot the signs of this crime so if they have any suspicions they can contact us and help us to build up our intelligence picture.
"Our proactive work – which we will publicise throughout the week on our website and social media channels – will help us to educate people about what county lines crime involves. Additionally it will help parents and carers in particular to know the signs to help stop children being forces into this crime.
“I want to stress that although members of the public and potential criminals might see a little bit more of us during this week of action, it in no way means our work to tackle this heinous crime isn’t happening 24 hours a day, 365 days a year.”
Mark Burns-Williamson said: “Disrupting ‘County Lines’ means helping to safeguard vulnerable people from exploitation and abuse, as well as ultimately reducing the blight of organised crime groups operating in our communities.
“We are potentially now in a better position to tackle this type of criminality. The Modern Slavery Act gives the police and prosecutors more options in going after the gangs behind these destructive activities.
“I will be fully supporting this week of action, doing all I can with partners to raise awareness of the signs and indicators of these crimes. We need to send a strong message to the people responsible for causing this harm that their exploitation and abuses will not be tolerated.”