El Palo Alto is thought to have sprouted around the year 940. Tradition holds that Gaspar de Portolá’s expedition camped beside it from November 6 to 11, 1769, though some historians think the camp was under another tree downstream.
It once had two trunks; one fell in the late 1800s. Smoke from steam trains and a falling water table nearly killed it in the 1920s, but decades of care by the city, Stanford, arborists and the railroad saved it. It is now about 110 feet tall, down from about 162 feet in the 19th century.
The tree stands in El Palo Alto Park beside the Caltrain bridge at the Menlo Park border. A 1926 plaque on a granite boulder marks Portolá’s camp.