Row hammer mitigation with randomization of target row selection

A memory device with internal row hammer mitigation includes randomization for selection of victim rows to refresh for row hammer mitigation. When memory devices connected in groups all use the same probabilistic determination of which row to select for row hammer mitigation, all memory devices could miss refreshing the same victim row, resulting in data loss. With randomization of the selection, the memory devices are more likely to select different potential victim rows for refresh, reducing the risk of data loss. The memory device performs row hammer mitigation during a refresh operation on a row selected based on a recent activate command. Selection of the victim row can be performed with a pseudo-random computation based on a value unique to the memory device in the group.