Lying in the rugged Coast Range some twelve miles north of San Francisco, the 28-square-mile Corte Madera Creek watershed drains southeasterly into the shallow waters of San Francisco Bay. The valley's communities of Fairfax, Sleepy Hollow, San Anselmo, Ross, Kentfield, Greenbrae, Larkspur and Corte Madera – the older ones dating back 120 years – together have a population of 55,000, most densely distributed on the valley floor, and thinning out as the elevation increases towards largely publicly-owned ridge land that reaches a height of 2571 feet at the East Peak of Mount Tamalpais.