This report describes the unique preschool participation patterns and demographic characteristics of low-income families in Silicon Valley. It is one of two studies conducted by the Urban Institute to examine participation in higher-quality early care and education programs among low-income children in Silicon Valley. The companion report (Greenberg, Adams, and Michie 2016) explores the barriers to early care and education low-income children of immigrants face in Santa Clara and San Mateo Counties, and identifies possible strategies to address them. (author abstract)