Abstract: A secure access port cover system comprises a cover and an access tool. The cover includes a base and one or more lids that are locked and unlocked via manipulation of a mechanical locking system housed within the interior of the base. A relatively small control port in the base provides access to the internal locking system. However, a specially adapted access tool is required to manipulate the internal locking system and move it between its locked and unlocked positions. Correspondingly, the access tool in one or more embodiments is a restricted-use item and not readily available to the public at large. Because the internal locking system can be manipulated only with the access tool, those not in possession of the access tool are unable to unlock the cover's lid(s) and unauthorized access to the underlying manhole or other access port is thereby prevented.