A hydrant locking device inhibiting unauthorized operation of a fire hydrant and includes a flip-top lid positioning between an open configuration and a closed configuration relative to a base. The flip-top lid is hingedly connected to the base of the locking device. The base may be releasably secured to an operating nut of the fire hydrant or more specifically an operating nut extension that engages the operating nut of the fire hydrant. The flip-top lid may also include a sealed cavity that may include electronics. These electronics may be in electrical communication with a wireless mesh network.