The spirit of the church can be traced to the 1820s, when a small adobe hut served as a place for worship for Spanish cowboys, or "vaqueros," who tended cattle owned by the Mission of San Juan Capistrano.
A small church and school were later built in 1880 near some long-dormant hot springs at what is now the intersection of Harbor Boulevard and Fairview Road.
In the 1940s, Baker Street was actually the northern edge of the Santa Ana Army Air Base, and soldiers attended Mass at a chapel there.
After World War II, part of the base near what is now Mendoza Drive became the Air Force Rocket Engine Facility while agricultural land thrived in its midst.
By the time the present-day church was built in April 1961, houses in the area were going for $18,900, notes the Rev. William Krekelberg, an archivist and historian for the Diocese of Orange.
"Purchases could be made with $800 down on a 25-year-loan at 6.2%," he notes in a letter to the Daily Pilot.
At the time, 600 families joined the parish. The next year, that number grew to 900.
Today, there are roughly 1,800 registered families in the parish, but the real number is probably close to 3,000, quite a few of them Vietnamese and Latino, said the Rev. Hildebrand Garceau, who came to Costa Mesa nearly six years ago from St. Michael's Abbey, just east of Irvine.
"It's a wonderful community that we have here," said Garceau, 59. "We're looking forward to the outdoor Mass. It's going to be very special for us — celebrating the Golden Jubilee."
A reception will follow.
Amanda Moss, 88, who's been attending St. John's more years than she can count, said she plans on being there.
"This church is awesome now," she said as she marveled at the relatively new stained glass windows, a recent gift from an anonymous donor. "It used to be a plain old church, but look at it now."
For those interesting in attending the special Mass, the church is at 1015 Baker St., east of Fairview.