Site information:

Monta Vista High School W parking lot, 21840 McClellan Rd, Cupertino

Plaque refers to "this arroyo" but I am not sure what it is referring to.  Nothing seems to remain of this feature.

37.315452,-122.057647

Plaque information:

State plaque

Plaque text:

Arroyo de San Joseph Cupertino

This arroyo honoring San Joseph, patron saint of flight and students, was first discovered and traversed by Spanish explorers in 1769. On March 25-26, 1776 Colonel Juan Bautista de Anza made it his encampment No. 99 as mapped by his cartographer Padre Pedro, before continuing on to the San Francisco Bay Area where he initiated steps to found a colony, a mission and a presidio.

Plaque placed by the State Department of Parks and Recreation in cooperation with the Cupertino Historical Society Inc. May 29, 1968.

Registered 12/23/1964