Six grave markers and a large monument bearing the Ruiz family name figure prominently in the Ruiz family cemetery in San Francisquito Canyon. They are the final resting places of Rosaria and Enrique Ruiz and four of their children, ages 8 to 30, who perished in the St. Francis Dam disaster of March 12-13, 1928.

Early California rancheros maintained their own family cemeteries on their lands. The Perea and Ruiz families, who farmed in San Francisquito Canyon in the mid-1800s, were no exception. The Ruiz family cemetery, as it's known, may have been the Santa Clarita Valley's largest private burial ground. It was actually started in 1888 by property owner Ramon Perea (8/31/1838 — 1/25/1915) upon the death of his wife, Antonia, who wished to be buried on the hill overlooking the Perea ranch house.

The cemetery lies on a tranquil hilltop approximately six miles south of the dam site.

— Notes from A.B. Perkins and Leon Worden.

Construction on the 600-foot-long, 185-foot-high St. Francis Dam started in August 1924. With a 12.5-billion-gallon capacity, the reservoir began to fill with water on March 1, 1926. It was completed two months later.

At 11:57:30 p.m. on March 12, 1928, the dam failed, sending a 180-foot-high wall of water crashing down San Francisquito Canyon. An estimated 411 people lay dead by the time the floodwaters reached the Pacific Ocean south of Ventura 5½ hours later.

It was the second-worst disaster in California history, after the great San Francisco earthquake and fire of 1906, in terms of lives lost — and America's worst civil engineering failure of the 20th Century.