Caller ID read Nicasio, CA, and the company behind the call is Senior Advantage Association, 1000 Van Ness Ave. Suite 104 San Francisco CA 94109, 866-620-0800. SAA peddles reverse mortgages. Nicasio is a small town located in Marin County, which is north of the City and County of San Francisco. Nicasio is a census designated area with a population of 96 in the 2010 Census. www.saareverse.com