One of the oldest private cemeteries in southern California, El Campo Santo, or "the sacred ground," contains the remains of the pioneering Workman and Temple families as well as Pío Pico, the last governor of Mexican California. Within its low brick walls, the one-half acre cemetery features a neoclassical mausoleum and a small cemetery plot surrounded by an ornate cast-iron fence.

In the early 1850s, the Workmans established El Campo Santo as a cemetery for their personal use. Along with a fenced-in burial plot, they built a Gothic Revival brick chapel, dedicated to St. Nicholas by Bishop Thaddeus Amat of Los Angeles. Among the first to be buried in the cemetery was William Workman's brother David, who was killed in 1855 while driving sheep to the gold fields in northern California.

After the Workman family lost the property around the turn of the century, the cemetery was neglected and its brick chapel was destroyed by fire. Walter Temple, a grandson of the Workmans, successfully filed a lawsuit preventing any further desecration of the cemetery. In 1917, he was able to purchase the cemetery and the surrounding seventy-five acres and began restoration. In place of the chapel, he built a cast stone neoclassical mausoleum and moved the remains of his family inside. He also transferred the remains of Ygnacia and Pío Pico from Calvary Cemetery in Los Angeles, which was relocated in the 1920s.

Today the cemetery is restored and maintained as a California State Historic Landmark and is open to visitors to explore on a self-guided basis. Free brochures are available in the Homestead Museum Gallery.