Newhall Ranch is the latest "new town" in the County of Los Angeles. GIS has been instrumental in the planning of this community, the future home for a population of over 65,000 people. FORMA Systems incorporated the full line of Esri software to identify, quantify, model, and analyze data to assist the planners in creating the Newhall Ranch Specific Plan. The cornerstones of the plan are the special management areas of the Santa Susanna Mountains' "high country" and the Santa Clara "river corridor," comprising more than 6,000 acres of preserved open space. FORMA Systems used ARC/INFO to document existing natural resources and their future value for preservation and enhancement. GIS defined compatible land use transitions and the "natural systems" integration of the community and the open space.