A memory device includes a data storage region and a spare column remap storage. The data storage region includes a plurality of sub-arrays, and each of the plurality of sub-arrays has a plurality of main columns and a plurality of spare columns. The spare column remap storage includes a plurality of storage units storing column address information of a repaired main column of one of the plurality of sub-arrays and address information of a repaired main column of another of the plurality of sub-arrays into at least one of the plurality of storage units included in the spare column remap storage.