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These data comprise extracellular recordings of neural activity in visual areas V1 and V4 of macaque monkeys passively viewing drifting grating target stimuli in isolation and under conditions of crowding (in the presence of distractor stimuli). All recordings of neuronal populations are from chronically implanted microelectrode arrays in both cortical areas of 2 male macaque monkeys. Animals were required to maintain fixation on a central point while stimuli were presented over the population receptive fields. Stimuli were presented for 0.25 s. Reported values reflect the total spike count of each neuron during the stimulus presentation. Target orientation was varied across an 18-degree range across presentations and, on a subset of trials, targets were surrounded by drifting grating distractors that varied in target-distractor spacing. Within an individual session, these same stimuli were also shown rotated by 90 degrees in orientation, to minimize the effect of adaptation. All trials (target orientation, distractor spacing) were randomly interleaved. A total of 15 sessions are included in this data set. Results from the experiments are described in: Feature representation under crowding in macaque V1 and V4 neuronal populations Christopher A. Henry, Adam Kohn Current Biology (in press, 2022)