The Mt. San Antonio Community College District was created in December, 1945 when voters of four local high school districts approved the formation of a community college district. Initially named Eastern Los Angeles County Community College, the institution was later renamed after Mt. San Antonio, the imposing, snow-capped mountain (popularly known as Mt. Baldy), prominently visible in the distance above the campus.
The 421 acre College site was originally part of the 48,000 acre La Puente Rancho. During World War II, the facility was converted into an army hospital and later a Navy hospital.
Mt. SAC opened in the Fall of 1946 with 635 students occupying a few Spanish-tiled buildings and temporary Navy barracks clustered below the San Jose Hills. Walnut, not yet an incorporated city, consisted of very little except dirt roads, cacti, and grasslands covered in the spring with wild mustard grass.
Quite naturally, the growth of Mt. SAC has mirrored that of the local area. From its humble beginnings with an initial enrollment of 635 students, the college now serves nearly 40,000 men and women from diverse backgrounds and generations. The College District boundries encompass the communities of Baldwin Park, Bassett, Charter Oak, Covina, Diamond Bar, the southern portion of Glendora, Hacienda Heights, City of Industry, Irwindale, La Puente, La Verne, Pomona, Rowland Heights, San Dimas, Valinda, Walnut, and West Covina.
Mt. SAC has emerged as a leader in education not only in the San Gabriel Valley, but in the state. It is the largest, single-campus community college district in California.