High Quality Content by WIKIPEDIA articles! Walnut High School is located in Walnut, California, among the San Jose Hills of the San Gabriel Valley in Southern California. It is a public school in the Walnut Valley Unified School District. The school is a two-time National Blue Ribbon school and five-time California Distinguished school (1991, 1992, 1994, 1998, 2005 and 2009). It has also offered the International Baccalaureate program since 1999.