Ontario Monclair School District Ontario, California
Nicknamed the gateway to Southern California, the city Ontario, as well as neighboring city Montclair, is home to the third largest elementary school district in California - the Ontario-Montclair School District (OMSD). Founded in 1884, the district also incorporates portions of the city of Upland and unincorporated areas of San Bernardino County, comprising 24,000 students in 26 elementary schools and six middle schools.