The school district’s original name was the Cajon School District. In 1878, at the suggestion of Sarah Jane McFadden, the name was changed to the Placentia School District. Placentia is derived from a Latin word meaning "pleasant place to live." The city name came from that change.
Placentia's climate and rich land attracted an ever-growing number of new residents. The area was well suited for raising citrus fruit, walnuts, avocados, and grapes. Placentia became the center of Valencia Orange Growing and Packing, and its 500 citizens voted to incorporate the City in 1926.
In 1960, Placentia’s population had reached only 5,000; however, a phenomenal growth period was just beginning. By 1970, the population had increased five-fold to nearly 25,000. Today, Placentia is still a fast-growing community with 45,000 residents, beautiful suburban homes, good schools, stately churches, and wholesome recreation.
In 1971, Placentia was honored with the prestigious "All America City" Award, given out annually by the National Civic League to ten cities in the United States.