This invention consists of a Level Sensing Device and Hydraulic Control Valve, which, when, as a team, is applied to a system with a Hydraulic Pump W/Oil Reservoir, three or four Hydraulic Jacks, three or four Normally-Open Solenoid-Operated In-Line Hydraulic Valves, and piped and wired as described in this document, will provide a completely automatic leveling system for Recreational Vehicles, such as, Motorhomes, Pick-up Campers, and Camping Trailers. This Leveling Sensor/Switch and Hydraulic Control Valve can also be retro-fit into any exsisting manually-operated or semi-automatic hydraulic leveling system and, as a team, make it a completely automatic leveling system.