Saint John Mountain, Mountain summit in Northern Coast Ranges, California, US

Saint John Mountain is a peak in the Northern Coast Ranges of California, standing at 2,048 meters (about 6,719 feet) just north of Snow Mountain in the Mendocino National Forest. It rises 554 meters above the surrounding terrain, and its base spans about 5.1 kilometers. The summit receives snowfall in winter.

The mountain served as a reference point for indigenous peoples long before European settlement in the region. Later it became documented as a geographic marker during California's early surveying and mapping efforts.

Saint John Mountain lies in Glenn County, about 14 km from Stonyford and just north of Snow Mountain in Mendocino National Forest. The name is shared with the surrounding terrain, where oak woodland and conifer forest cover the slopes and only about two people per square kilometre live. Visitors notice the Mediterranean climate, with around 919 mm of rain a year and July averages near 28 °C.

Visitors should prepare for changing weather conditions at the exposed summit, where wind and rapid temperature shifts are common. Carrying sufficient water and sun protection is important regardless of the season when climbing.

The rising elevation zones support different plant communities, transitioning from oak woodlands at lower levels to dense conifer forests near the peak. This shift becomes visible as you climb from the base upward.