The Grossmont Union High School District is a public school district located in eastern San Diego County, California, and serves high school, adult school, and Regional Occupational Program students in the cities of El Cajon, Lemon Grove, and Santee; the unincorporated communities of Alpine, Casa de Oro, Crest, Dehesa, Dulzura, Jamul, Lakeside, Mount Helix, Rancho San Diego, and Spring Valley; most of La Mesa, and parts of San Diego. Wikipedia