An orientation singularity is rapidly detected in a display of iso-oriented elements, but its location may be coded imprecisely. We describe the exact shape of such pop-out at different positions in the visual field. The figure shows a trial sequence. Stimulus arrays were 9×9 (as shown) or 5×5, with about 4000 trials in each condition. Results show that localization was more accurate in the dense array, where there were more distracters, and more potential target locations. Errors were frequently directed toward distracters near the target. Their distribution over the visual field was inhomogeneous, with most errors for targets at larger angles of visual eccentricity, above and below fixation. Some observers made systematic errors to horizontal neighbors of the horizontal target, and vertical neighbors of the vertical target, especially in the sparse array. Accuracy was greatest for targets far from the previous response location. Most subjects showed significant learning effects. However, the greatest determinant of error size and direction appears to be an individual propensity to make specific errors to targets in a particular location. This may reflect inhomogeneities in the underlying cortical topographic representation.