Although the adobe wasn't restored and designated as a historic landmark until 1953, its history stretches back to…More the mid-18th century and before.
In 1769, the expedition led by Spanish Captain Gaspar de Portola (who would come find the San Francisco Bay) camped in Pacifica's San Pedro Valley, near the Sanchez Adobe site. Before Portola's arrival, an Ohlone Native American village was located in the area, and some of the tools made of shell, stone, wood and bone that they used can be seen in the Sanchez Adobe Museum, located on the historic site grounds.
Later, Spanish missionaries would use the site as an agriculture hub, as they could not farm very well on the sand dunes where they lived and worked in present day San Francisco. Missionaries also converted Native Americans living near the adobe to Christianity, and records from 1792 indicate that many Native American deaths, attributed to an epidemic, occurred around the same time.
Today, visitors to the site can see where the foundations of the original structures rested (they're outlined with logs), take a tour of the site, view historic shows of craft and cooking and peruse the museum inside the current adobe structure.