Thursday, September 24, 2026

Question: Morro Rock stands guard at the mouth of Morro Bay’s harbor as the last in a line of nine extinct volcanic peaks running inland toward San Luis Obispo. What is this chain of peaks nicknamed?

Answer: The Nine Sisters. Morro Rock is the seaward peak in this chain of nine volcanic plugs, formed roughly 23 million years ago, that runs from Morro Bay inland to San Luis Obispo. Portuguese explorer Juan Rodríguez Cabrillo named the 576-foot rock “El Morro” in 1542, and today it’s a California historic landmark and a peregrine falcon sanctuary.