San Bruno Mountain, Mountain park in San Mateo County, California, US.

San Bruno Mountain is a peak in San Mateo County, California, standing near San Francisco Bay with an elevation of about 1,300 feet. The landscape includes open grasslands, forested valleys, and small streams that flow through the different terrain.

The mountain's south flank borders the cemeteries of Colma, most laid out after San Francisco evicted all its burial grounds in 1912. On the east, a gravel and crushed-rock quarry opened in 1895 and supplied material for SFO runways and US 101. The 1941 Cow Palace arena stands in the Bayshore neighbourhood at the mountain's foot.

The mountain's name comes from San Bruno, and its slopes above the Bayshore inspired Malvina Reynolds' 1964 song "Little Boxes," a hit for Pete Seeger, about the tract housing built around the mountain after World War II. Sign Hill in South San Francisco has carried large letters since the 1920s.

The protected area spans over 900 acres with multiple trails and entry points from surrounding towns. Visitors should come prepared for varied trail conditions and wear comfortable hiking shoes.

The mountain's serpentinite outcrops near Serbian Ravine and Point San Bruno give rise to serpentine soils whose minerals support rare plants, which in turn feed the Callippe silverspot, Mission blue and San Bruno elfin butterflies. The low-growing bearberry Arctostaphylos uva-ursi, native here, is now widely planted in drought-resistant landscaping.