- The San Juan Elementary School District is the oldest in Orange County, having existed as one of five school districts of Los Angeles County in 1850. (Orange State College Foundation)
- The first teacher in Orange County was Thomas J. Scully. He taught from 1854-1855 in both Santa Ana and San Juan. He was paid $100 and would teach 3 months in one area, then pack his books in his saddle bags and travel on his horse to the other district for 3 months. (A History of the San Juan Capistrano School District by Fred L. Newhart, 1966)
- Back in the 1850's most of the land in the mission valley was ranch and farm land and most families spent their days working their land. In 1856, there were about 200 school-age children living in the area, but only about 15 attended school on a daily basis.
- Most of the families were only interested in their children learning the basic subjects such as reading, writing, and arithmetic. Most children only attended primary grades and then returned to work with their families.
- In the early 1900's, the walnut crop was the valley's principal crop, and every school-age child was needed to help pick up the nuts.
- There were four different school buildings on the current site of San Juan Elementary School. The first was an adobe building in 1850 where San Juan Grammar School was started. The second was actually two wooden buildings which were built in 1871.The third was a stucco building built in 1911 and the current brick buildings were built in 1963.
- In 1947, the school board built The Teacherage, a duplex house which is still located on Spring Street, to provide housing for the principal and his family on one side and the teachers on the other side.
- Harold Ambuehl, who eventually became superintendent, was also a teacher, secretary, coach, and principal of San Juan School.
On May 17, 2016, the Orange County Historical Commission hosted a ceremony to unveil a plaque designating San Juan Elementary School as a historical site. The school was established in 1850 and is the oldest school site in Orange County.