A locking assembly attachable to a manhole cover includes an arm disposable in a lowered position with the arm disposed in a first orientation engageable with a manhole frame supporting the manhole cover to inhibit removal of the manhole cover from a manhole frame, and disposable in a raised position and in a second orientation operable to allow removal of the manhole cover from the manhole frame. In an embodiment, the locking assembly may include the arm attached to a movable member having a spiral, helix, or curved groove and in which the movable arm is receivable in a bushing and a pin receivable in the groove.