n the Norwegian Arctic, petroleum exploration is prohibited north of the ice edge (the zone between solid sea ice and open ocean); the mapping and definition of the ice edge becomes the boundary for petroleum exploration. However, no evidence-based scientifically ‘correct’ position of the ice edge exists. Defining the ice edge—and its geographic positioning—is the result of co-production processes involving multiple actors and practices. We explore how the use of a new dataset for determining the geographical position of the ice edge became the centre of a proxy debate over how far north petroleum exploration should be allowed. The analysis reveals how maps serve as visual discourses in debate, and a strong correlation between different definitions of the ice edge and political commitment to petroleum activities. We challenge and discuss the performativity of maps and how mismatches between expectations to knowledge-based management, including maps, may have democratic implications.