A recent development in drug markets across England and Wales garnering increased attention is the phenomenon of ‘County Lines’. This involves drug supply groups migrating from major cities to smaller towns, and has become associated with a range of harms including violence and the exploitation of vulnerable populations. Drawing on interviews with police officers of various ranks tasked with responding to County Lines, this article explores how they are interpreting this emergent phenomenon. A framework of profit maximisation was constructed by all of the participants, and was used as a way to understand and explain some of the key characteristics and activities associated with County Lines groups. Congruent with this, participants also stressed these group’s similarities to legitimate business and how they adopted conventional business strategies such as marketing. The article concludes by discussing the utility of this profit maximisation framework, how it relates to police responses and areas worthy of further research.