Det Ch Insp Gary Stratton said: “This week’s activity sends a clear message to those involved in county lines.
“We will find you, we will seize your drugs and weapons, and we will protect the people you seek to exploit.”
Some 237 people were arrested but police declined to comment on the exact number of suspects who had since been charged.
But the force confirmed arrests were for offences including possession of a Class A and B drugs, possession of an offensive weapon, drug driving and possession with intent to supply.
County lines refers to drug dealing in which organised criminal networks use mobile phone lines to move and supply drugs, often exploiting children and vulnerable adults to move drugs, weapons and money.
Project Medusa also played a key role in Operation Vanguard on 4 March, where 300 officers executed warrants, conducted roadside checks and carried out land searches in Anfield.