Tustin Unified School District was created from the 1972 voter-approved unification of the Tustin Elementary School District and the Tustin Union High School District. It is located in Tustin, a city in Orange County, California. Its district territory comprises Tustin, the unincorporated community of North Tustin, and parts of the cities of Irvine and Santa Ana. It has 18 elementary schools, five middle schools, four high schools, one K-8 school, and one adult school.

Santa Ana is a city in and the county seat of Orange County, California, United States. Located in the Greater Los Angeles region of Southern California, the city's population was 310,227 at the 2020 census, making Santa Ana the second most populous city in Orange County, the 13th-most populous city in California, and the 64th densest large city in the United States. Santa Ana is a major regional economic and cultural hub for the Orange Coast.