Provided herein may be a memory system and a method of operating the same. The memory system may include a host configured to generate and output a host command and a host address and to receive and store host map data, a controller configured to store map data, generate an internal command in response to the host command, and map the host address to an internal address based on the map data, and a memory device configured to perform an operation in response to the internal command and the internal address, wherein the controller is configured to load, when the map data corresponding to the host address is not stored in the controller, new map data into a map data storage area storing map data that is identical to the host map data.