A storage device may include, at least one memory device including at least a first single-level cell (SLC) region, a second SLC region, and at least one multi-level cell (MLC) region, the first SLC region having a higher data read speed than the second SLC region, and the second SLC region having a higher data read speed than the at least one MLC region, and a storage controller configured to control the migration of data among the first SLC region, the second SLC region, and the at least one MLC region.