A memory device includes a nonvolatile memory having a first block and a memory controller configured to exchange data with the nonvolatile memory. The memory controller includes a first processor to divide the first block into first and second domains, a second processor to generate a reclaim signal by determining whether to perform reclaiming on each of the first and second domains and a third processor performer which reclaims each of the first and second domains according to the reclaim signal and merges the first and second domains.