Magnetic extensometers are installed in boreholes or fills to monitor settlement and heave associated with construction, mining, and tunnelling operations. Data obtained from the magnetic extensometer can indicate settlement zones as well as total displacement. The system consists of a probe, a steel measuring tape, a tape reel with built-in light and buzzer, and a few magnets positioned along the length of an access pipe. The magnets are coupled to the surrounding soil and move up or down as heave or settlement occurs. Readings are obtained by lowering the probe through the access pipe to find the depth of the magnets. Settlement and heave are determined by comparing the current position of each magnet to its initial position.