Nonprofit providing children facing adversity with enduring, professionally supported one-to-one relationships that change their lives for the better, forever. Our mission is to provide children facing adversity with strong and enduring, professionally supported, one-to-one mentoring relationships that change their lives for the better...forever. Big Brothers Big Sisters of the North Bay merged with Big Brothers Big Sisters of the Bay Area (23-7108045) in 2017. BBBSBA now serves children, families and volunteers in nine Bay Area counties, including Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano and Sonoma.