Morro rock is the northern-most of the nine sisters, located in the city of Morro Bay.

1883 illustration of Morro Rock

It was given the name El Morro in 1542 by the explorer Juan Rodriguez Cabrillo.¹ The word morro just means a rounded hill or a headland. Some other sources have called it Moro (Moor) explaining that it was named for resembling a Moorish turban.

Until 1936 it was an island, but then over a million tons of rock were blasted from Morro Rock, in part to form the causeway leading to the Rock from shore as well as the Morro Bay breakwater.¹ In 1963 the blasting ended, and by 1968 the Rock had been declared a California Registered Historical Landmark, and in 1973 an ecological preserve (peregrine falcons nest there), and so it is now protected from further such damage.¹

Notes

1. Sharon Lewis Dickerson Mountains of Fire: San Luis Obispo County’s Famous Nine Sisters—A Chain of Ancient Volcanic Peaks EZ Nature Books (1990), pp. 58–64, 66–67