The Calla High campus on the southeast corner of East Highway 120 and Austin Road can trace its roots back to 1901.That’s when the first school of the 20th century was built in San Joaquin County. Back then, there were 35,452 residents in the entire county. Today, Manteca alone has 78,000 residents while San Joaquin County has 726,000 residents.Ten residents in the Calla area petitioned the county for a school.