Cerro Romualdo is a 1,300-foot (396 m) mountain in San Luis Obispo County, California.

The mountain is the fifth in a series of volcanic plugs called the Nine Sisters.

[2] The mountain is named for a Chumash man who received the 117-acre (0.47 km2) Rancho Huerta de Romualdo Mexican land grant from Pío Pico, the last Mexican Governor of Alta California.

[3] In the 1890s, rock from Cerro Romualdo was used in the construction of the Southern Pacific Railroad.

Cerro Romualdo is owned by the State of California, and is used by the California National Guard at adjacent Camp San Luis Obispo for fitness training.