Justin-Siena is a day and boarding Catholic high school in the Lasallian tradition offering a college preparatory program that serves more than 650 young men and women in grades 9–12. Founded in 1966 by the De La Salle Christian Brothers and the Dominican Sisters of San Rafael, the school is located on forty acres in the City of Napa. Justin-Siena serves a diverse student body from the Napa and Sonoma Valleys and Solano County.