San Andreas Creek

San Andrés Creek , now called San Andreas Creek, is a perennial stream that flows 5.9 miles southeasterly along the San Andreas Fault from Sweeney Ridge in San Mateo County, California, providing the inflow to and outflow from San Andreas Reservoir, and then entering Lower Crystal Springs Reservoir, where it was a historic tributary to San Mateo Creek. San Mateo Creek then carries its waters over Crystal Springs Dam northeast to San Francisco Bay.

After discovering San Francisco Bay from Sweeney Ridge on November 4, 1769, the Portolà expedition descended what Portolà called the Cañada de San Francisco, now known as San Andreas Creek, to camp just south of the San Mateo Creek canyon on a lake called by him Laguna Grande, now covered by Upper Crystal Springs Reservoir. The campsite is marked by California Historical Marker No. 94 "Portola Expedition Camp". After heading south and descending from the foothills along San Francisquito Creek to established his base camp at El Palo Alto, Portola retraced his steps and returned along San Andreas Creek to recross Sweeney Ridge and then via the coast back to San Diego. The San Andres Creek place name is shown on the Rancho de las Pulgas 1856 plat map. Padre Palóu, on an expedition from Monterey to explore the western side of San Francisco Bay led by Captain Rivera, renamed Portola's Cañada de San Francisco to Cañada de San Andrés on November 30, 1774, it being the feast day of St. Andrew. Captain Juan Bautista de Anza, after forging the first overland route from Monterey, California, to San Francisco Bay, explored the peninsula and selected the sites for Mission San Francisco de Asís and the Presidio of San Francisco. De Anza returned to Monterey via the Cañada de San Andrés and camped on the banks of San Mateo Creek on March 29, 1776. In de Anza's diary on March 29, 1776, he wrote: "Night having fallen, at a quarter past six I went down to the arroyo of San Andreas and to another, that of San Matheo, where it descends to empty into the estuary."

Wikipedia