A memory device is provided as follows. A memory cell region includes a plurality of blocks, each block including a plurality of NAND strings. A control logic divides the plurality of blocks into a plurality of block regions based on a smaller distance of a first distance with respect to a first edge of the memory cell region and a second distance with respect to a second edge of the memory cell region and controls an operation performed on the memory cell region using a plurality of bias sets of operation parameters for the operation. Each bias set is associated with one of the block regions.