An occupancy monitoring device includes an occupancy sensor for detecting occupancy of a physical location by an object, a communication submodule for transmitting a wireless communication mode of a status of the detected occupancy and an unique identifier of the occupancy monitoring module, and a battery powering the occupancy sensor and the communication submodule. Components may be housed in an enclosure that is further attachable to a permanently fixed element. An occupancy monitoring system includes a plurality of the occupancy monitoring devices being deployed to monitoring occupancy of locations. Status and ID messages transmitted from the occupancy monitoring devices and receivable a user device, thereby allowing displaying a graphically representation of locations that are occupied and locations that are unoccupied.