Investigators believe the large metal gate was taken sometime Monday afternoon from the entrance to a rural property in the southeastern corner of the district (at 41200 Old Yale Road.)
The gate had been installed one month earlier to prevent access to the area that has been the scene of unruly bush parties, reports of gunshots and illegal dumping.
A neighbour reports seeing a dark coloured pickup truck with a white trailer in the area on Monday afternoon.
Police would like to talk to anyone who may have spotted a similar vehicle at around the time of the theft.
No suspects have been identified.