Abstract: An enclosed sliding door assembly for simply and efficiently sealing a doorway is disclosed. The enclosed sliding door assembly is further advantageous in that it has a configuration that is designed to protect its elements from environmental and corrosive conditions. The enclosed sliding door assembly comprises a housing enclosing a drive mechanism and a door movably and operatively engaged to the drive mechanism. The housing of the assembly is further configured to form a track portion that provides for both a linear length of sliding travel and a contoured length of sliding travel, respectively, for the door. The drive mechanism within the housing is further configured to cooperate with the track portion formed by the housing, such that when the drive mechanism slides the door along the track portion, the door can be moved between an open position and a closed position.