This report describes a design that serves as an early warning system for movement in a large slide mass. The mass threatens the construction of the Grand Coulee Feeder Canal Modification. This slide hampered construction of the original canal to the point that a complete redesign was necessary. Comments on a more generally useful system are included. The Land Movement Monitoring System (L.M.M.S.) is centrally controlled by a digital computer to automatically scan a 600 m long portion of the slide, at 123 points within the mass, every 14 seconds. The system draws attention to minor movements. An automatic alarm activates when movements exceed limits programmed into the system. A permanent record is made. Data may be automatically translated into graphics. The L.M.M.S. was constructed of readily available components. It can be used to monitor any size and type of existing or potential land movement. This initial system cost about $1900 per monitoring point, most of which will be recoverable.