Various animals use an internal sense of heading to aid navigation, but the underlying neural circuits are unclear. Green et al. used tethered flies walking on a ball to examine the role of neurons that directly connect the protocerebral bridge and the ellipsoid body of the fly central complex in this process. As flies turned to the left or right, these cells showed peaks of activity that moved across the bridge such that their positions tracked the fly's heading. Blocking the activity of one of the cell types in the bridge impaired heading tracking in the dark, whereas activating such cells predictably changed the heading signal, suggesting a circuit for angular integration in flies.